There are 2 tendons that attach the bicep to the shoulder, the long head and the short head. These tendons are flexible bands of tissue that help your muscles and bones move. Pitchers will feel pain or discomfort in the front of the shoulder. The pain level will vary from mild to severe and is caused by inflammation and swelling of the tendon.
The pain is created from a number of reasons ranging from mechanics, improper warm-up/conditioning to over/under use to physical weakness and instability.
Treatment can often start immediately after feeling pain or discomfort. If the pain is low-to-mid intensity, some basic stretches or light strengthening exercises will relieve the pain immediately. Other times it may take a few days. In most cases taking a couple days off from throwing will let everything calm down enough to begin a strength, flexibility and short range, low intensity throwing program. THERE IS HEALING POWER IN THROWING!! There should usually be a level of throwing that can be done without pain, to speed up the recovery process and maintain consistency with the throwing motion.