Pain and tingling in my right arm?

Wondered if anyone could help me with a little more info on maybe what to expect. In January of this year I started with a burning sensation in my right arm pit, I went to the docs and he thought it was maybe the start of shingles a rash never came and the pain never left. I went back to the docs because the pain was now all down my right arm and tingling in my fingers also my right hand goes dark purple if I try to exert it. I was referred to the hospital for physio when I got there after examining my arm she has now referred me to a specialist as she suspects nerve damage or nerve infection. Has anyone got any idea what will happen next im in agony should i rest it or keep trying to move it