muscle spasm
"I have muscle problems in my upper and lower back from carrying drums in drumline in high school. My back hurts constantly every day (but a very tolerable and mild pain). But those of you with back problems know that you have good days and bad days. On the bad days I started taking 800mg Skelaxin, and it did absolutely nothing for my pain. It provided the same amount of relief that 2 or 3 Aleve provides."