LulaMoon,
As myopracticworks stated, this can be coming from several places. The fact that you have numbness and tingling, means that the nerves are involved somewhere.
Since it is only one extremity, that usually rules out a systemic problem (such as diabetes or thyroid problems). So, the nerves could be getting irritated anywhere from the spine to the peripheral nerve. Since it is the whole upper extremity, it would be difficult to have that many nerve roots in the spine affected all at one time (though not impossible). So, it is more likely to be located in a place where many of the nerves are close together, as in the brachial plexus or the thoracic outlet.
So, you have several options on who to see. You could see a neurologist, orthopedic surgeon, or a physiatrist (specialist in PM&R - physical medicine and rehabilitation, who deal with all sorts of musculoskeletal and neuromuscular problems).
Good luck.