Have tmj, getting worse. Having difficulty opening mouth to yawn.?

TMJ. You possibly have a muscle spasm. You should see your dentist. For now you can try a soft diet, warm compresses( some patients do better with cold?), Ibuprofen if it is ok for you to take it, light massage in the area in front of your ears (TMJ) your dentist can verify if it is a dental problem or not.
Displaced disc? Sounds like you may be developing a "closed lock" of the tmj, due to a displaced disc. This can be best seen on an mri. Sometimes this will respond to conservative treatment including medication or possibly splint therapy. However, the highest success rates in relieving pain and restoring normal function have been achieved with TMJ arthroscopy, where a small scope is introduced into the joint.....
See Expert in TMJ. Sounds like your TMJ problem is getting worse. See a TMJ expert. Any dentist can be a TMJ expert with the proper training and experience. Most commonly, oral surgeons, prosthodontists, and orofacial pain specialists. Ask your MD, your dentist and your dental society for referrals.
See TMJ Dr. The symptoms of tmj/tmd can vary from mild (clicking, popping) to severe (locking, headaches, ear problems, facial pain, inability to function and eat properly.) if it gets worse, the symptoms can affect other bodily systems and then the overall health complex can be compromised. Deal with it early!