Aches and pains

Let the record show that I felt FINE when I left the house this morning--so why am I a wreck right now?

Some background: I've been having muscle spasms in my back on and off for about three days now. Pain-killers dull the pain but don't stop the spasms; muscle relaxants stop the spasms but also knock me out, so I've been trying to tough it out until the weekend. Yesterday the pain was so intense that it hurt to breathe, so I went home early and went for a long walk through the fall countryside.

After the walk I felt significantly better, and the lack of pain allowed me a good night's sleep for the first time all week. And when I left the house this morning, I felt great. The spasms started up again just as I was stepping out of my car, and they haven't stopped.

Is it my car? My shoes? My midterm stress level? I can't blame my office chair because the spasms started before I ever sat down. (Some years ago I was forced to use a chair that caused me pain every day of my life--but that's another long and not terribly interesting story.) Something is making my back spazz out and it's not making me very happy. I'm getting really boring about it: "Gather round, children, and let me tell you about my aches and pains...." But right now pain is all I can think about, which makes me not a very fun person, but I can't go home early today because I have a 4:00 meeting. I'm already tired of listening to myself whine. There must be a solution somewhere, but what is it?