Left arm weakness and shoulder pain: what to know

Pain that stays around the shoulder and worsens when lifting may fit a tendon or joint problem, such as Rotator Cuff Tendinitis, Shoulder Impingement, or Rotator Cuff Tear. Pain with marked loss of movement can occur with Frozen Shoulder or Shoulder Osteoarthritis. Calcium deposits can irritate a tendon in Calcific Tendinitis.

Neck pain, tingling, numbness, or weakness travelling below the shoulder can point toward Cervical Radiculopathy. The side alone does not identify the cause. A clinician may compare both arms, check sensation and reflexes, assess neck and shoulder movement, and decide whether imaging or other tests are needed.

Avoid heavy lifting and repeated overhead work while the weakness is being assessed, but keep the shoulder gently moving within a comfortable range. Note when the symptoms began, which movements trigger them, and whether grip, hand sensation, or neck symptoms have changed. A physiotherapy or medical assessment can help separate a shoulder problem from a nerve problem.

Seek emergency help for sudden arm weakness with facial drooping, trouble speaking, severe chest pressure, breathlessness, fainting, or unusual sweating. Arrange prompt clinical review for weakness after an injury, rapidly increasing weakness, a visibly deformed shoulder, fever with a hot swollen joint, or pain that prevents normal use of the arm.

Could the weakness come from my neck, shoulder, or another nerve? Which examination findings would change the next step? Should I temporarily avoid a particular activity, and which gentle movements are appropriate? Do I need imaging or a referral if strength does not return?