My back is throbbing and will for the next day or so (because, you know, my menstrual cramps are more like contractions than regular abdominal cramping), and my hip just started screaming at me, and there's a headache brewing because I've been clenching my teeth again and not getting enough sleep, and come to think of it, my neck and shoulders are a little tight too....
So, today is not the day I get motivated to exercise. Today is one of those days I try to get through without embarrassing myself or biting anyone's head off.
Chronic pain (and stress) can suck it. Pass the ibuprofen. And chocolate. Especially if you know what's good for you.