Have you put this into your search engine for answers, put in Zanaflex and side effects, also the pharmacy may help they can put it into their PC there,I know there are side effects from a lot of meds and the warnings are usually on the label. I am getting some similar pain but mine is not so bad, it came on after I was prescribed Penicillin and took strong pain Meds and had dental work done , I am still a mystery but not taking any other prescribed meds that make me ill.