A rotator cuff tear can develop gradually from repetitive arm motions – especially overhead motions common in sports. A sudden tear can be caused by a traumatic fall, or by lifting a heavy weight incorrectly. The risk increases with age. The injury typically causes pain in the shoulder, even when you are at rest, and increases when you lift your arm. Your arm may feel weak and, in some cases, you may not be able to lift your arm.
Related: Rotator Cuff Tear