What Causes Numbness In Hand While Sleeping?

my arm and hand go numb all the time when i am sleeping it wakes me at least 3 times in the night, when i am on the treadmill i have to run at some points with my arm down by my side, holdng the steering wheel of car in a certain way it goes numb, i have been to see doctor and was given anti inflamatries which are not doing anything. i remebered yesterday that around the time this started i had a big electric shock up my arm, could this be the cause and be more serious than i think?