The rotator cuff is a group of muscles and tendons that surround the shoulder joint. These muscles keep the ball of the upper arm bone firmly within the shallow socket of the shoulder. A rotator cuff injury can cause a dull ache in the shoulder that worsens at night.
Rotator cuff injuries are common and increase with age. These injuries may occur earlier in people who have jobs that require repeatedly performing overhead motions, such as painters and carpenters.
Physical therapy exercises can improve flexibility and strength of the muscles surrounding the shoulder joint. For many people with rotator cuff problems, these exercises are all that's needed to manage their symptoms.
Sometimes, rotator cuff tears may occur from a single injury. In those circumstances, people should seek medical advice quickly because they might need surgery.

Rotator cuff injuries can range in severity from simple inflammation to complete tendon tears.
The pain associated with a rotator cuff injury may:
Some rotator cuff injuries don't cause pain.
Your family healthcare professional can evaluate short-term shoulder pain. See your care team right away if you have immediate weakness in your arm after an injury.
Rotator cuff injuries are most often caused by progressive wear and tear of the tendon tissue over time. Repetitive overhead activity or prolonged bouts of heavy lifting can irritate or damage the tendon. The rotator cuff also can be injured in a single incident during falls or accidents.
The following factors may increase the risk of having a rotator cuff injury:
Without treatment, rotator cuff problems may lead to permanent loss of motion or weakness of the shoulder joint.