Why does rotator cuff tendinitis cause pain when lifting the arm?

The rotator cuff helps keep the upper arm centred while the arm rises. With tendinitis, an irritated tendon may become more sensitive as it contracts and moves beneath nearby structures. The shoulder can therefore hurt through part of the lifting arc, especially during reaching, dressing, swimming, or placing an object overhead. Repeated loading may leave an ache after activity or make the area uncomfortable at night.

This movement pattern does not identify one diagnosis on its own. Shoulder pain with elevation can also arise from other tendons, the joint, the neck, or an injury. An examination considers the exact arc, resisted strength, neck movement, and the effect of rest.

Temporarily reduce the height, repetition, or load of movements that reproduce the pain, while continuing easy shoulder motion. Keep objects close to the body rather than reaching far overhead. Do not repeatedly lift the arm to check whether it still hurts. A physiotherapist can adjust technique and prescribe gradual mobility and strengthening once the tendon tolerates loading. Arrange assessment if symptoms persist, limit work or sleep, or began after a distinct injury.

Seek prompt care after trauma if you suddenly cannot raise the arm, notice deformity, or develop marked weakness or numbness. Urgent assessment is needed for shoulder symptoms with chest pressure, breathlessness, faintness, or sweating. Seek a timely review for fever, a hot red shoulder, rapidly worsening pain, or loss of movement.

Which part of the lifting movement is irritating the tendon? How should I modify work or exercise? When can I safely add resistance? What other causes would you consider if the pain does not settle?