I've had this problem for nearly 10 years and no doctor has been able to give me a diagnosis: I suffer from a tingling sensation in my right shoulder blade. When I feel the tingling, the trapezius muscle becomes very sore. Aside from the tingling and muscle pain, I feel a sort of itching sensation, but no matter how much/forcefully I scratch, I cannot relieve the pain. Subsequently, the skin in this area has become slightly numb. Over the years, the pain inflicted area has seemed to increase outwards over my shoulder and upwards towards my neck. These sensations occur at completely random times and do not seemed to be triggered by anything specific like stress, heavy lifting, exercising, etc. It occurs often enough and becomes so uncomfortable that I am seeking medical attention again.