Why does my left arm hurt when I put it down but not when I lift it up?

Generally, the main causes of pain when lowering the left arm but not when lifting it include muscle fatigue or strain, localized cold exposure, rotator cuff injury, lateral epicondylitis, and shoulder periarthritis. If discomfort occurs, it is recommended to seek timely medical evaluation and treatment at a正规 hospital. Specific analyses are as follows:

1. Muscle Fatigue or Strain

Repeated use of the left arm or lifting heavy objects recently can lead to muscle fatigue. Pain may occur during relaxation of the muscles when lowering the arm, due to stretching of damaged tissues. Reduce activity of the left arm, avoid lifting heavy objects, gently massage the arm muscles, and apply a warm towel to the painful area for 15–20 minutes at a time to promote recovery.

2. Localized Cold Exposure

Prolonged exposure of the left arm to cold environments causes cold-induced constriction of blood vessels and muscle irritation. Changes in muscle tension when lowering the arm may trigger pain. Dress appropriately to keep the left arm covered and prevent further chilling. Soaking the arm in warm water can improve circulation and relieve muscle tension.

3. Rotator Cuff Injury

Damage to the rotator cuff tissues around the left shoulder joint results in less stress when lifting the arm, but increased traction and pain when lowering it, which aggravates the injury. Under medical guidance, medications such as celecoxib capsules, diclofenac sodium sustained-release tablets, or glucosamine hydrochloride capsules may be used. In severe cases, arthroscopic rotator cuff repair surgery may be required.

4. Lateral Epicondylitis (Tennis Elbow)

Inflammation of tendons at the lateral epicondyle of the left humerus leads to pain when lowering the arm, as the inflamed tendons are stretched. Under medical supervision, medications such as ibuprofen sustained-release capsules, loxoprofen sodium tablets, or naproxen sodium tablets may be taken. Combined with local immobilization and rest, severe cases may require surgical release of the lateral epicondyle.

5. Shoulder Periarthritis (Frozen Shoulder)

Inflammation and adhesion of tissues surrounding the left shoulder joint cause pain when lowering the arm, due to stretching of adhered tissues during movement, exacerbating inflammatory stimulation. Under medical guidance, drugs such as etoricoxib tablets, methylprednisolone tablets, or chondroitin sulfate sodium tablets may be prescribed. When necessary, shoulder arthroscopic release surgery may be performed, followed by gradual rehabilitation exercises postoperatively.

In daily life, maintain warmth of the left arm to avoid cold exposure; avoid overuse to prevent muscle strain; perform adequate warm-up exercises before physical activity to reduce injury risk; rest promptly when pain occurs to prevent worsening; and undergo regular joint check-ups for early detection and treatment.