I got TMJ after the endodontist hit my nerve twice with the needle practically sending me through the roof. Of course, he denide it had anything to do with this. I was in EXTREME pain for nearly a month to the point I was wishing the pain would go away or I that I would die. I would rather suffer the pain of giving birth than go through TMJ pain again! No one could offer me a solution. I tied 2 other dentists, another endodontist, a ear nose throat docter....nothing! I was about to drop out of my Kung Fu classes due to the pain when the Grand Master offered to try and help me using what he called "Showlin Healing techniques". I was very skeptical but he was not charging me for it and I had no where else to turn so I tried it. Three sessions later. "I'M Healed!". I still get a painfull jaw when I visit the dentist (holding my mouth open for long periods of time) or when I am under extreme stress but nothing coming close to the pain I was experiencing back then. I am sold on this healing technique. Another name for it is "Healing Hands". It was high energy emitted out of the hands as heat and combined with deep tissue massage. You might find one in your area. Also, I was told UCLA has a medical department dedicated to TMJ. Try giving them a call if you are in the area.
You seem to have a lot going on. TMJ dysfunction has many different causes. The pain you are experiencing can be attributed to the TMJ or the tooth that was worked on. i don't think it has any relation to the injection at this point.The antiinflammatories may work in the short term but I believe that the cause of the problem must be addressed. My suggestion is that you see a doctor(dentist) who specializes in TMJ problems.You can call your local dental society for a referral or if there is a dental school in the area that might be a good place to go.