This thread is two years old...just so you know...
I doubt the Flexeril is a contributing factor. It is one of the tamer muscle relaxants and I have never had a problem with it. Actually it didn't do much for me and I was on far higher amts with other things -- didn't help much w/spasms, phase me or help with sleep. (I may have developed a huge tolerance for things.) Apparently SOMA is addictive so if the dr suggests that you might reconsider. Then again it seems everyone thinks everything is addictive.
Personally I still have muscle cramps, spasms, aches etc after 8 months of aburtply stopping opiates (morphine & roxis) in ~ 5 days. Bananas help to a point. I just live with it and appreciate the moments not cramped -- I get the feet/toe, leg and hand cramps like when you cramp from swimming. Motrin OTC helps some but honestly not enough to bother taking it. I really had no idea what coming off a ton of meds would be like -- wish I had some clue. Hydro is viocodin or percocets (?) - it should be fairly manageable. I would probably taper over a week and then go CT but that is ME.
I would check with your doctor, read more, and take the flexeril.
O.k., I just literally four days ago got off of a 10-year Vicodin/Norco addiction. I thought to myself, "I cannot live with all of this muscle tension and pain." Then I myself tried acupuncture yesterday. OMG. My entire right side (which had started out with a shoulder injury ten years ago) was ALL blocked up . . like a brick. Head to toe . . Two hours later . . .through massage and needles, I felt absolutely NO pain whatsoever. Even though I called in for a prescription for Flexiril, I don't think I am going to pick it up . . think it is time I learn to manage stress and relax than to rely on a synthetic to "relieve it for me." Just my opinion. BTW, I was also given "liver herbal supplements" by my acupuncturist to start clearing out my system after years and years of narcotic and psychotropic medication . . .wow. I feel like a new woman already . . . going back on Thursday for my second appointment. It feels like a miracle. Hope a little of this is helpful to someone.
Sorry I'm not sure if the Flexeril could be causing this, but one thing I'm sure causes muscle spams is lack of potassium. You can buy potassium in pill form in any drug store or eat lots of bananas & potato's.