I have had TMJ for years.  I have been to an oral surgeon a few times for my problem.  He has x-rayed and the x-rays show that my jaw joints are deformed.  I don't know if they were always that way or whether they got that way over the years.  I have had physical therapy with great success, and I also wear a retainer at night because I tend to grind my teeth when I sleep.  Anyhow, if you didn't have TMJ before and have noticed it right after you fell, perhaps a chiropractor could help you.  Maybe you knocked something out of whack when you fell. 

My tmj came on this yr out of the blue. Matia said she was shoked i hadn't had it before and that most of her patients have it.she told me it would go away once my body is ballanced. I don't really do anything except sometimes i will massage my jaw and inside my mouth i was taught how to do this by a massage theripist. I only do it if it's really bad. I am kinda used it it. I also realized I had been cleanching my teeth so i got a mouth gard and that has helped some.