Cortisol as a single parameter is very limiting when it comes to explanatory power. 
Sometimes useful as a rough screening tool for very rare diseases of the hypothalamic–pituitary–adrenal axis.

If you want to really check your adrenal function, this is what you should do:

Saliva samples:
- Cortisol (early in the morning: 0-1,5h)
- Cortisol (after 1,5-3h)
- Cortisol (after 3-6h)
- Cortisol (after 6-9)
- Cortisol (after 9-15h)

- DHEA (early in the morning)
- DHEA (after 12 hours)
- Cortisol/DHEA-quotient (mornign/12h)

If I find time this weekend, I can go into more detail on why you should do this but I am very busy at the moment.
The other stuff was already correctly adressed by the other members.
Take care

@RedLine Jesus this turned into a monster if a text hehe.
Pain is really negative emotion that you are not cognizing as emotion. It's good that you are cognizant of this pain and have some insight to it's nature, most people are too numb to even notice.
All emotions exist in the body. The placement of these emotion are mapped out by the chakra model.
The way to resolve all this is to fully go into the pain, get to know it and then transform it into the positive expression that it seeks to become. It's clogged up energy but it's still energy and thus has tremendous potential. It is seeking to go from its current solid form to a more moving and transforming form which is liquid form, and then to a blissful, spacious, liberated gas form.
This pain will not disappear into nothing but rather unfold into something positive, something you have been seeking for a long time, like grounding, power, self-assertion and self-expression.
This is an intuitive, gentle and intimate process. Using hard shit for this kind of healing is the wrong paradigm. Psychedelics could aid this intimate process, a low dose of something like lsd that doesn't give you hallucinations could be a good aid, but any crazy psychedelics seem unfit for you right now. You can fix all of this sober. With the right understanding, wisdom and techniques you have that power. 
 
If the pain in your chest comes from fear then I would guess that its strongest in your solar plexus and emanates from there. This is a minor chakra that's between the naval and the heart chakra and can negativity impact both when closed. In its open state it's tranquil and serene, in its closed state it's anxious. This functionality is closely related to the root chakra which is in your perineum, near your anus. In its closed state it's fearful and uncomfortable and in it's open state it's grounded, secure and comfortable. For this I recommend the protective bubble technique, it will sooth both chakras.
Protective bubble technique 
Imagine that you are inside a bubble with the diameter of roughly your length. The ball is about 4 inches thick and made out of a transparant material that is glowing with beautiful light. The bubble should be felt as an intelligent energy, rather than dead materia.
Inside this bubble you feel completely safe, embraced, tranquil, joyful and loved. Both feel these qualities emanate from within you and feel like you are receiving this from the bubble.
The walls of the bubble are semi permeable, good energy such as love and joy flow freely through the walls. But negative energy such as domination, suppression, unloving expectations or anything that is less than completely loving and accepting, is kept out by the walls. I’m talking about negative energy both from people and our thoughts, perhaps the idea of our mother or father.
This bubble subconsciously symbolizes your boundaries.
If negative energy gets through the walls against you will, it might be a sign that you need to set and articulate boundaries in relation to the negative entity. This is a function of the throat chakra. In your head, talk to the intruding entity, be intuitive. Ask it what it wants and establish boundaries with it. Listen to what the entity wants but don't comprise with it. Try to articulate why it's wrong. Let love be the mediator here.
If the bubble feels limiting in any way that means that you are not letting good energy flow through it. Let go of the limiting feeling but keep the healthy boundaries.
The visualization itself is only a tool to get in touch with the subtle sense of how your boundaries should be. Keep the subtle sense and the attitude throughout the day.
The point of this is to cultivate healthy boundaries and the attitude that we won’t tolerate negative energy, boundary violations or threats from the outside. There is absolutely no good reason to ever be affected by other people’s unloving, negative energy. There is no good reason to not be fully happy right now! It’s about allowing yourself a level of happiness that is unwisely seen as unacceptable by others and our culture.
When you have established a health bubble, just sit and bask is self-love, self-acceptance and happiness, while protected by the bubble.
You can stay an bask in this wellbeing or you can continue into the other techniques.
The contracting of the throat is the throat chakra. As you know, it's repressed stuff. You have things that you want to say and it remedy is to say it.
Self-expression technique - can be done after establishing the protective bubble or by itself.
In your head, say the things that you hold back or anything that pop into your mind. Some key words here are "I feel ...", "I want ..." And "I like ...".
Example: "When this person did that I felt unloved and betrayed. I want him to apologize and I feel resentful that he hasn't."
Like this you articulate in your mind clearly whatever you are thinking. Let it be a stream. Really get into it. 
As you keep going you might want say things aloud. Let the process evolve naturally. Whatever works for you is the right way to do it. When you really get into it you might want to scream and shake and go crazy as your energy gets unstuck. That is progress you don't have to verbalize your screaming but definitely flow with the energy and don't suppress it energetically. When you have purified your emotions you will eventually find that these emotions have clouded a profound gratitude that will reveal itself. Don't force it. Express good things if it comes naturally.
Pay extra attention to your throat while doing this. You can try to incorporate the breath into this by breathing deeply and relaxing your throat and do the self expression on the out-breath.
Start with this exercise as it will begin to purify your other stuck energy, not only your throat chakra.
I'm guessing the reason you have become accustomed to suppressing yourself is because your parents suppressed your will and your expression of that will as a child. A suppressed will is an angry will. So some of your anger might be directly liked to this suppression and might be remedied by the self-expression technique.
 
The bubble and the expression technique should dissolve some of your blockages but probably not all of it. For that you should get into the chakra and open it to it's happy state.
Overview of chakra system, find more precise placement of chakras on google:
Chakra name Solid, closed, repressed state, passive Liquid, closed but active and transforming state, has a will to seek catharsis in gas state Gas, open, happy, blissful, cathartic Element(the solid, liquid, gas form of energy is only metaphorical and not related to element which is a deep aspect of our psyche and cognition) Root  Ungrounded Fearful Grounded, secure Earth/physicality Sacral Alienated, lonely Horny, approval seeking Embracing, passionate, lively, connected, orgasm Water/movement Navel Submissive, victim complex Angry Joyful, benevolent power Sun/warmth, change, vitality Solar plexus(minor chakra) Withdrawn Anxiety Tranquility, serenity None Wish tree (minor chakra, located right under heart chakra and is connected to it and it's love. Many think these are one and the same chakra and they almost are, so you can see this as an aspect of love) Nihilistic Longing Fulfilled, purposeful None Heart Apathic Hatred Loving, healing Air/spaciousness, sky Throat - doesn't have an emotion in itself but is rather a conduit for previous chakras Suppressing  Expressing discontent Expressing content, gratitude Ether - irrelevant Head - also doesn't have an emotion in itself. Is the ego itself, the master chakra. All other chakras are mirrored here as thoughts and are controlled from here.  Unconscious Dualistic, ego awareness, closed-mindedness, dissociation Non-dual, boundless awareness, happiness, open-mindedness None Crown - melting together with the cosmos - irrelevant in this context All chakras influence the others and all are effected by physical conditions like lack of sleep or poor nutrition. So your healing won't take as long for every chakra as when you open one you positively impact the others. The heart chakra has the biggest impact on the overall system as it's the healing chakra. So you want to fist focus on the heart chakra to then use its love in healing the other chakras.
 
You wrote that the chest pain also is anger which I would guess is actually felt strongest lower down around your navel area and parallel vertebrae. You wrote that you also experience anger in your head. This is a missing of the anger in your navel chakra. All lower chakras are mirrored in our head as thoughts. If the energy is stuck in our head tho I would think it means the anger is combined with dissociation from the anger. This is healed by going into the anger and resolving it instead of avoiding it. Own up to the anger instead of casting it to the shadow.
Use this technique to open the remaining chakras (although use the previous technique for the throat chakra):
Chakra catharsis release technique - can be done after establishing protective bubble or by itself
Choose a chakra to work on, this can be changed after a while i you like. Find where in this area you feel the most energy, either in solid, painful form or in liquid form.
Take a deep breath. On the in-breath, bring up the liquid form of the chakra you are working on the most energy-dense point. Feel the energy radiate outwards from this point and don't restrict the energy to this point at all. Make it as intense as possible, the intenser the liquid form, the more solid energy is transformed to liquid, and the stronger the eventual catharsis. 
On the out-breath transform the liquid form into its cathartic gas form. The liquid form has a seed of the gas form in it. Find that positive crenel in the liquid form and go into it while letting go of the negative aspects of the liquid form.
There are two additions to add to the out-breath step that you can add when you got the hang of the basic technique:
Combine the positive expression of the chakra with love. This turns root chakra comfort and security to flourishing, sacral chakra pleasure into loving embrace, naval chakra joy into generous nourishing, and head chakra awareness into loving surrender. On the out-breath also tune in to the chakras element. Root chakra: tune in to the physicality of earth, the space you are in and your body sitting on earth, feel grounded. Sacral chakra: tune in to the water element, it's a warm and embracing water, feel it all around. Feel the density of the water. The world is in constant cyclical movement like ebb and flow. Flow with the world, breath with that flow and feel your stomach and chest expand and contract. The water element is what connects us with the world. Feel that connection with nature as you breath with the world. Just like nature ebbs, flows, turns from night to day your body ebbs and flows with the breath. Like Bruce Lee said: Be like water my friend. Naval chakra: feel a sun in your belly, radiating your powerful love outwards, warming and nourishing the entire world with it's blindingly bright light.  Heart chakra: tune in to spaciousness. The spaciousness of the room you are in, of your body and lungs. Imagine your body being hollow. Breath the spaciousness, breath love and feel how spacious love is. Feel how still and how peaceful it is. Breath deeply. Feel that spaciousness expand infinitely. It's soothing. It's indestructible.  Let's use the navel chakra as an example, on the in-breath feel a powerful anger radiating from your gut. On the out-breath find the kernel of joy and benevolent power in the anger and go into the happiness of that while letting go of the painful negative aspects of the anger. As you breath out you radiate that cathartic, powerful joy.
Hold the out-breath for as long as comfortable and just bask in the bliss of the positive expression(gas form) of the chakra.
Once you have gotten in to the positive open gas form of the energy, stay with that on the in-breath too and forget about the liquid form if it feels right.
It can be a bit tricky to get this technique right, there are many subtle distinctions to make and you have to experiment a bit to get this all right. Take this process in your own hands and follow your intuition. Whatever feels right to you is what you should do.
Be a little careful with going into the power of the navel chakra as it can increase your overall prana and make the painful chakras even more painful. If you feel this happening, then focus more on the blissful joy side of the chakra and less so on the power side of the chakra. Or switch your focus entirely to dissolve other pain or focus more on the heart chakra.
For more information on these techniques and more complementary techniques, I highly recommend 5-Minute Miracle by Tara Springett.
Pro tip: make the last meal before doing these exercises only fruit, preferably water rich fruit. Fruits are the most prana rich foods on the planet and will get your energies moving. I myself am enjoying good vibes and high energy on an entirely fruitarian diet.
I'm glad you reached out with this because everything is healable and everyone deserves healing. Hope all this is insightful and helps. Let me know how these techniques work for you or if they don't, or if you have any questions. 
Lastly here is a great song about life and healing: https://youtu.be/sg209CadVQM
 

Eric Weinstein also has his own wiki with a lot of contributions to systems thinking:
https://theportal.wiki/wiki/Main_Page

I am getting such a mentalgasm from this.