What Causes Numbness And Pain In The Middle Of Jaw Bone?

Hi - for the last couple of weeks I have felt a "numbness" in the middle of my right jaw with some occassional twitching. Now I can feel it on both sides but no twitching. ocassionally it feels warm inside. the feelings are noticable but not too irriitating. What could it be? My teeth don't hurt but I do gridn my teeth at night