Did this dr say if it is NTOS or VTOS?
Or maybe you can tell- ntos is nerve based and vtos is more vascular based.
There is a RSI type that is a mix of those and non specific. (simplified descriptions)

Usually lifting, holding ,carrying weighted items, depending on fitness level may start a flare up.
Delayed pain is often a case too, so awareness of what sets you off and the timing is really something each has to figure out.
Usually reaching up overhead , holding arms out in front will be a issue.

If head , shoulders are hunched or forward of the body (check with side view).
That posture closes down the area where many nerves & blood supply need to fit thru- opening up the chest & collar bone area with aligned posture may help to relive many symptoms and pain.
Posture correction is retraining yourself & your muscles so it does take time & work.

Some simple things you can try-
http://neurotalk.psychcentral.com/album.php?albumid=422