Any abnormal sensation in lower extremities (legs or ankles—which includes pain, cold legs or feet, crawling sensation etc) while trying to sleep is usually due to ‘restless leg syndrome’(RLS). The leg pain of RLS typically eases with movement of the legs (resulting in shaking of legs) and becomes more evident at rest or while you are asleep. Usually cause of RLS is not known but few medications such as lithium, antidepressants and beta-blockers (such as bisoprolol) can trigger the symptoms. Other reasons of RLS could be rheumatoid arthritis, kidney failure, diabetes or any underlying heart disorder. In addition restless syndrome has been found to be associated with stress, fatigue, magnesium deficiency, vitamin B-12 deficiency, anemia and other systemic diseases.Though there is no permanent cure of RLS, regular & sound sleep helps get relief from symptoms. Supplements of iron/vitamin also help some. Sometimes medications such as levodopa, bromocriptine, oxycodone may be tried to provide some relief from the symptoms. Avoiding alcohol, caffeine, and nicotine may partly relieve your symptoms. Other useful measures are stretching, alternate hot and cold packs or baths, massage and applying vibrators on the feet and legs before bedtime. Relaxation and meditation can also help. Do discuss this with your doctor and get yourself examined. Take care!