Swimmer’s shoulder is a condition in which one or both shoulders are painful to the touch. It can be caused by overuse and/or injury to the rotator cuff muscles, which are located on the back of the shoulders.
The most common cause of swimmer’s shoulder is overuse. Swimmers tend to use their arms more than other athletes, and they may not stretch out their arms before swimming. This causes an imbalance in the muscles of the shoulder, causing pain. Injury can also cause swimmer’s shoulder, usually from a fall or from hitting your arm on something while swimming.