hmmm...that is really odd. Sounds like a trip to a doctor will probably be needed, unless the dentist examined your jaw? I don't really think TMJ/TMD is the sort of thing that generally pops out of nowhere, unless you have suddenly started grinding or clenching your teeth. (If you clench while sleeping, you can usually tell by running your tongue along the insides of your cheeks, if so, you will usually feel a line along the inside, roughly where your teeth would come together.)

I have a severe joint malformation on one side, there is lots of popping and cracking, sometimes the joint locks and I cannot open my mouth, I have migraines, have difficulty eating hard or chewy foods,etc. I can easily say though it has never involved my teeth at all - no pain there.

Everyone of course is different, I really think your best bet would be to see someone who could examine the jaw & related muscles surrounding that area, perhaps even a Primary Care Physician to start. I think you should pester your dentist a bit more, too.

Chiropractic adjustments have never worked for me, I would always feel great for the first ten minutes, and then everything went back to the way it was. I think it is because with my Fibromyalgia, all the muslces are affected, so it just keeps putting pressure on my jaw/joint.

I hope you feel better soon!