The Fluttering In My Right Arm Near My Back Where

The fluttering in my right arm near my back where it meets the shoulder. It seems to stop when I raise my head upward. It comes and goes but has persisted for about 3 days now. I recently had a cold that I am recovering from and I am a type 2 diabetic for the last 25 years taking insulin and Metformin. Can you tell me what it is. I can actually see my arm moving.