muscle spasm
"I have fibromyalgia and additional pain from osteoarthritis.  I work fulltime at a demanding professional job, and and taking opiates and/or muscle relaxants like cyclobenzaprine frequently is not an option - I need to be able to think.  The fibro pain disappears when I take methocarbamol and it doesn't (seem to) affect my ability to think, nor does it make me sleepy.  It works very well for me."