Restless Leg Syndrome may be medically diagnosesd or you may simply find that that leg movement or cramping may disturb your sleep.

These symptoms often respond well to taking a Magnesium supplement such as Bioceuticals "Ultra Muscleze"

Restless Leg Syndrome is also made up to 3 times worse by taking anti-allergy medications that contain an antihistammine.  See: http://www.medicalnewstoday.com/articles/129785.php