Shoulder pain involves any pain in or around the shoulder joint.

The shoulder is the most mobile joint in the human body. The rotator cuff in the shoulder is made up of four tendons. These tendons give the shoulder a wide range of motion.

Any swelling, inflammation, tearing, or bony changes around these tendons causes pain when a person tries to move the arm above the head, behind the back, or straight out in front.

The tendons pass underneath a rigid bony arch in the shoulder. The most common cause of shoulder pain is when the tendons become trapped under this arch. The compressed tendons become inflamed or damaged, a condition called rotator cuff tendinitis. This can occur from:

• General wear and tear as you get older
• An activity that requires constant shoulder use, such as baseball pitching, or work activities in which you need to raise your shoulder
• An injury

Shoulder pain can also be due to:

• Arthritis in the joints around the shoulder (gradual narrowing of the joints and loss of protective cartilage).
• Bursitis (inflammation of a fluid-filled sac, or bursa, that lies between tendon and skin or between tendon and bone). Normally a bursa protects the joint and helps make movement more fluid.
• Fractures of the shoulder bones.
• Frozen shoulder syndrome occurs when the muscles, tendons, and ligaments stiffen up inside the shoulder and make any motion painful and difficult.
• Inflammation of nearby tendons, such as those connected to the bicep muscles of your arms, from overuse or injury.
• Dislocation of your shoulder, which is when the ball-shaped head of your arm comes out of the socket.