Sounds like you are grinding your teeth at night when you sleep. I do that and have TMJ. I use a night guard because I am chipping my teeth. I also take flexeril at night to relax my jaw.

I take codeine and paracetamol. At night I take 2 codeine and paracetamol so I can get some sleep. Codeine when taking 2 can act like a sleeping tablet

it could also be arthiritis

Yes I agree... because this is associated with stress at night when you sleep we sometimes tighten our jaw. do you wake up with you mouth tight? this is part of the problem a mouth guard from dentist help is has been great for me...

Ice pack. You should get it checked to make sure it is TMJ. You could also have an infection. With the TMJ-Fibro it can feel like you have a bad tooth but if you wait a day or two the pain will move to a different tooth or area of the mouth. With a bad tooth, you will feel the pain in that tooth, on that side of the mouth all the time. I've also gotten infections in my gums which will give me simular pain which is why I said you should get it checked to be on the safe side.