I would think that looking down does it for the numbness. Try setting a timer on the phone so that you can do neck stretches and exercises. Google some!
That makes sense. Thanks! I'll look up some stuff. My shoulder/neck/back definitely get sore too so those will be useful but I think at least with with issue it's mainly my hand/wrist. I think probably from holding the phone too though. I just meant when my hand is numb it bothers my whole arm/feels weird but maybe I'm weird lol