Boy, was I wrong!
As I was getting some breakfast fixings out of the fridge, every muscle in my back contracted sharply. The pain was worse than ever! You could probably hear me a couple of blocks away!
I've spent the hours since then lying on the couch, wincing whenever a deep breath or slight movement sets off more spasms, and wondering how the hell I'm going to be able to sing tonight. I've called my massage therapist to see if she'll do a short-notice housecall, but I'm not holding out any hope. :(