your jaw is a tension point.. so probebly your carrying all your tension in your jaw.. try doing relaxation such as just laying still and thinknig about relaxing your jaw
(i myself suffer from jaw problmes and iv been to the hospical about it, they gave me a special thing to put in my mouth when i sleep so that my joints in my jaw dont hurt from stress)
Tensing your jaw is probably something you do when you are concentrating when you are stressed out. I do something similar – tense my jar a bit, and bite the inside of my lip. Sometime I do it long enough that it starts to bleed – that is how much we can have these tics without realizing it.
A few suggestions:
– Make it a point to remind yourself to relax your jaw while practicing. You might need to make it a mantra (“Relax the jaw, relax the jaw,” repeated to yourself throughout class.). Or, try to get into the habit of reminding yourself once per posture to relax your jaw.
– If reminding yourself what NOT to do doesn’t work for you, try to remind yourself to either smile or breathe. You might feel a bit silly to smile while doing yoga, but really, we practice because we like it, right? You don’t have to have a big grin, but a small smile will keep you relaxed and happy.
– Remember to breathe. Learning to control your breath is a big part of yoga, and I bet that if you are thinking about breathing, you will become more aware of your throat, mouth, and therefore your jaw.
One of the great benefits of yoga is the self-awareness and focus you can develop. Sounds like you are already developing that self awareness since you know your jaw is sore, so the next step is to move on to that focus! Good luck.