I Have Always Been A Side Sleeper. In The Last

I have always been a side sleeper. In the last 4-5 months, I have been awaken by pain from the top of my arm to my fingers. The top of my arm feels like it is asleep and as it travels down my arm to my fingers it feels like pain. My fingers are the worse, where it feels like burning and very painful. I change from side to side several times during the night. The pain has been lasting longer and longer. Right now it takes about an hour to go away. I have to get up an walk around shaking the arm in question. I have tried sitting up in bed and shaking my arm to relieve it but it doesn't seem to help. My right arm pain last longer than my left. Any ideas?