Strangely enough, this might be a symptom of Restless Leg Syndrome. It's also known as Willis-Ekborn syndrome now, since RLS never really described the disorder well. Willis-Ekborn causes an uncontrollable urge to move the limbs, usually the legs but sometimes the arms as well. The sensation is sometimes described as crawly or electrifying. It occurs when you are at rest, and improves with activity. I have W-E, and it can really negatively affect your life if left untreated. The symptoms can range in severity from mildly annoying to absolutely agonizing. Taking any sort of sleeping aid or anti-anxiety medication usually makes the condition worse.