When I enter a meditative state some muscle tension starts to build in my jaw, upper neck and to an extent the back of my head (where the neck meets the back of the head). The deeper the meditative state becomes, the stronger this tension becomes. It's almost like this muscle tension is an indicator of the depth of my meditative state (though I have other indicators of course). I have no idea why I'm experiencing this, it is completely involuntary and I can only keep consciously relaxing these muscles again and again.  If I intentionally focus on these muscles - as in temporarily making them my meditation object - the tension just becomes even stronger, to the point where it becomes unbearable cramping, which is painful. It's a bit irritating and I feel like it keeps me from going into an even deeper state because it's kind of distracting. Has anyone here experienced something like this? Do you think I'll just have to live with it or can this be overcome? Greetings.