So yesterday, I wondered aloud what I would do if I had no injuries to complain about. This is why you shouldn't taunt the universe.
Today, Friday, was to be a rest day. I was pretty tight in the legs when I woke up this morning after my PT beating yesterday, so I decided to go to the gym to stretch, do a little bit of core and my PT exercises, and then sit in the hot tub and stretch some more. I was doing the bicycle sit-ups when all of a sudden, my upper back locked. Between my shoulder blades. I laid back down, then stood up and gently tried to stretch out a bit, and nothing. It's a solid mass of tightness and pain. When I breathe deeply, my lungs expanding is pressing into the place that hurts. I tried some gentle stretching in all directions, and it just brought more pain.
So I made my way to my car, and drove home, and then sat in the driveway for 20 minutes letting the seat warmers roast my back. When I stopped crying, I came inside, took 4 advil, and got into a hot shower, where I stood under the water until the hot ran out. And now I'm back in bed, laying on top of the electric blanket because I can't find my heating pad, cursing the day I decided to get off my fat ass again.
I talked to my PT, and they are able to squeeze me in at the end of the day, but I don't know if this is a "stay off it for a couple of days" or "your spring racing season is totally fucked" kind of thing. Fingers crossed for the first.