Have you hurt your shoulder? Have you been doing too much with that arm? You don't say - however, bursitis could be your problem or an impingement in that shoulder. That could also cause the numbness. A doctor would probably prescribe a pain killer - surgery would be the last resort if there is an impingement.
Sounds like carpal tunnel. Repetitive use of the hand is usually one of the main causes of this condkition such as a cashier or use of a computer for long hours. I used to use a wrist brace thru out the day & even when I slept. It gave me some relief. I didn't opt for surgery, but many people choose this route with positive results, but you really need to consult your physician. This is an unprofessional diagnosis. Hope this is helpful to you.