I often get restless leg syndrome when I'm trying to go to sleep. It's caused by drinking Coca-Cola too late in the evening. It's the caffeine in the Coke that's the culprit. I also get restless leg syndrome and other muscle twitches if I take Benadryl, sinus headache medication, decongestants, or cough syrup. I can't remember what the name or names of the chemical is that's common to those medications. It might have been phenylpropanolamine. Dextromethorphan also does it to me. I also got the twitches when I ate or drank something that had a particular chemical in it, but I can't remember the name of the chemical (might have ended in ephedrine) or the food or drink that it was in. Sorry if this hasn't been much help. You should probably see a doctor.