I Have Pain In My Right Arm Right Where The

I have pain in my right arm right where the bicep and tricep meet. The right shoulder aches sometimes right on the top/tip. If I reach back with my right arm, the pain can feel like I have just banged my funny bone. It goes away in maybe 20 or 30 seconds. I have been on chemo and have had Neulasta, but that was 4 months ago. If you can help, that would be great. Two doctors have their own opinion but I still have the pain. Thanks!!