Shoulder pain: Pain in the shoulder due to an injury or disease. The design of the shoulder joint is such that it sacrifices stability for mobility. As an extremely mobile joint that plays a central role in the action of a major extremity (the arm), the shoulder is at high risk for injury. An injury can involve the ligaments, bursae, or tendons surrounding the shoulder joint, the cartilage, menisci (plural for meniscus), or bones of the joint. Pain can also occur in the shoulder from diseases and conditions that involve the shoulder joint, the soft tissues and bones surrounding the shoulder, or the nerves that supply sensation to the shoulder area.