I could have written this reply myself Nappy. Seriously Holly, there have been times when I didn't know if my arm numbness was caused by MS, the old rotator cuff injury or from a developing Carpal Tunnel Syndrome. Like you, mine comes and goes which seems to rule out MS.

I don't actually know what a PCP is..... but I'm assuming it means Primary Care Provider which would translate to GP in Australia.

I too suggest he/she should be your first port of call and often as not, a bit of physio will be all it takes to improve your symptoms. If not, then they're the right person to refer you on to the appropriate specialist.

Good luck Holly. Let us know how you get on.