I keep waking up with pins and needles in my left hand?
It's idle hands. Watch yoself
you are probably sleeping in a position that is putting pressure on a nerve.
Do you sleep on your side?.. If so this is probably your problem.. Try sleeping with your hand under the pillow that way it's out of the way and its not direct pressure. I am 100% sure if you do this you'll wake up free of pins and needles free.