Rotator cuff injuries: The rotator cuff is a group of muscles and tendons that stabilize the shoulder joint. Injuries to the rotator cuff, such as tears or strains, can cause shoulder pain. These injuries can occur due to repetitive motions, overuse, trauma, or degenerative changes.

Shoulder impingement: Shoulder impingement occurs when the tendons or bursa in the shoulder become pinched or irritated, often due to repetitive overhead activities. This can cause pain, especially when raising the arm or performing certain movements.

Frozen shoulder (adhesive capsulitis): Frozen shoulder is a condition characterized by stiffness and pain in the shoulder joint. It occurs when the tissues around the joint become thickened and tight, limiting mobility.

Shoulder arthritis: Arthritis can affect the shoulder joint, leading to pain, stiffness, and reduced range of motion. Osteoarthritis, rheumatoid arthritis, and other forms of arthritis can contribute to shoulder pain.

Shoulder instability: Shoulder instability occurs when the structures that hold the shoulder joint in place, such as ligaments or the labrum, are damaged or loose. This can result in shoulder pain, a feeling of shoulder dislocation or instability, and recurrent shoulder dislocations.

Bursitis: Bursitis is the inflammation of the fluid-filled sacs (bursae) that cushion and lubricate the joints. Inflammation of the bursae in the shoulder can lead to pain and limited mobility.

Tendinitis: Tendinitis occurs when the tendons in the shoulder become inflamed or irritated. This can cause pain and discomfort, particularly with movements involving the affected tendons.

Shoulder fractures or dislocations: Fractures or dislocations of the bones in the shoulder can result in severe shoulder pain. These injuries often occur due to trauma or accidents.

Referred pain: Sometimes, pain from other areas of the body, such as the neck or upper back, can radiate to the shoulder and cause shoulder pain.

Other causes: Other factors that can contribute to shoulder pain include muscle strains, nerve impingement (such as with a pinched nerve in the neck), certain medical conditions, or referred pain from internal organs.