Your shoulder has several joints that work together in order to make certain movements. Even though all joints are susceptible to injury, it is most common for injuries to occur at the largest joint, where the shoulder blade and arm connect. Generally when pain in the shoulder joint is diagnosed, the doctor refers to this main joint. Any injuries to the other, smaller joints are called by their name.

The reason the main shoulder joint is injured so often is because it sits in a very small, shallow socket. However, if the joint was not in such a shallow socket, you would not have the range of motion necessary to accomplish most daily jobs. When the rotator cuff tendons that surround this shallow socket become inflamed, it results in rotator cuff tendonitis. Anti-inflammatory supplements like Celadrin can go a long way to reducing the pain from this condition, but it's best to see a doctor right away.