Left Arm - Stings

 this just started recently. off and on my left arms stings.
almost like there is a needle in it. i wonder if it
may be arthrithis (SP) because when i try to lift something
the arm feels weak. I thought maybe sleeping
but i changed and dont sleep on that side.
Has anyone else had something like this?

I am pretty good with vits/protein/calcium
just  need more water, my last labs came back all ok.

In July this year, I fell down on my left side and hit my elbow really hard..I was really sore for a long time but recently some of that has still been lingering. I do believe it's carpel tunnel because it effects my arm from my elbow to my wrist and my one index finger..carpel tunnel will effect ONE finger or a couple of them, never all of them...for me, it's because I'm on the computer too much..

I hope you get some answers.