I have had pain in the back of my right arm, slightly above the bicep, and below the shoulder. I attempted to throw a snowball last December, and it has been painful since. It hurts when I reach behind me, or quickly lift my right arm above my head. The pain lingers for several minutes, sort of like a cramp. It really does not feel like it is in the shoulder (ie. tear in the rotator cuff), but more like a muscle pull that won't go away.
It sounds like you may have a torn tendon, I had the same symptoms that went on for months until I finally went to a doctor and got and MRI, I had torn my extensor tendon half into, it takes months to get over this type of injury due to the fact that blood flow to tendons is so low.
This site complies with the HONcode standard for trustworthy health information.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. Med Help International, Inc. is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.