I Had Gotten A Rash, The Quickly Vanishes. Then My

I had gotten a rash, the quickly vanishes. Then my same arm started to hurt with like a pain that you have hit your funny bone over and over. Then my two lower fingers kinda went numb, but still can move them just fine. but they are very sensitive to heat and cold as well as touch. The pain from my shoulder down to my finger can be intense. Their feels like something is crawling on my shoulder most of the time. Going to have a never study done tomorrow. Just hope they can figure it out.