JP, I had my head examined once with a MRI machine. They didn’t find anything wrong me. Take that you conservatives out there :)
I hear you about claustrophobia! I’m not either, but I just about become one after that experience.
I have a neighbor whose back got so bad she couldn’t even sit for more than 5 minutes. I don’t know her exact diagnosis, but she did two things and one of them seemed to pretty much cure her. She started a walking routine; evidently that strengthens/balances back muscles. She also went to a chiropractor and he put her on a very expensive machine that expanded her back (or something?). Between those two things, she’s back to normal.
I hope your MRI results come back negative and it’s just muscle or tendon strains. Best wishes.