Check out Thoracic Outlet Syndrome. if i sleep on my back, both arms go numb, on the sode, that side goes numb, if i sleep sitting up, both arms go numb. My doc just pointlessly sent me to get my neck x rayed without feeling around for knots. i told her i have scoliosis and have been to a chiropractor. the X rays came back normal, which is the only time they ever have.

TOS is getting pretty common, it seems. There's also cell phone elbow.