Does anyone have experience with leg and/or foot pain and cramping when trying to get to sleep?

I don't know if what I'm experiencing is what doctors call "Restless Legs Syndrome". About 3 nights a week I get some of the most horrible cramping of the muscles in my calves or feet while trying to fall asleep. If I've been especially active during that day and on my feet alot, that night is HORRIBLE when it comes to trying to fall asleep. I'll get cozy, my CPAP humming, and then the legs or feet start cramping and hurting and I can't move or straighten them to "undo" the cramp; its agony! It doesn't happen every night, but often enough to be a bother. I know there is a prescription drug for "restless legs" but frankly I'm "drugged out". I take enough perscription meds as it is for my allergies, asthma, etc. I don't want another "drug".

Are leg & foot problems while trying to sleep common for OSA patients? Anyone found a way to cope with it? Some days are much better than others and some days the cramping doesn't happen at all. But on the days it does...HELP!