micro,
Oh no, I have been there, done that with my lower back.
I use a partial roll of paper towels, not too thick, and put it on my spine and lay on my back, when it starts to go. Usually can tell a problem's in the offing when one leg is longer than the other, indicating the pelvis is twisting. A block below the hip can put it back in position and take the stress off the spine. The paper towels push things back in place. At least that's my theory.
Don't know if the paper towel trick would help mid-back, but it might if something is bulging out. That said, I'm no doctor and you don't want to make it worse. It all depends on what's happening with the spine.
I also got a lot of relief when I found a position in the reclining chair that worked, with one of those compressible-type back pillows.
Muscles? Maybe a heating pad? I don't know, usually ice first...
Hope it comes around quickly.