When my MS first really reared its ugly head, they thought it was a pinched nerve, so doc gave me
flexeril... My body reacted much the way you just described, it was everything was
in a state of muscle spasm. Granted at the time, we just thought it was the 'pinched nerve' and I was tense, never thinking flexeril took things to the next level :)
It went on for about 3 weeks and then I finally started wondering about the flexeril.... The doctors had no clue why I reacted this way..