My right jaw has been stiff and sore on a pretty consistent basis for probably about a year or two now. It never truly gets locked up, but every once in awhile, I'll go to open my mouth and it'll feel like something broke for a split second on its way open, like it was locked for just a millisecond and then broke free. This week has been especially bad. I'm finally going to see a dentist on Monday; hopefully if they can't do anything about it, they might at least be able to help identify the issue and point me in the right direction.