Differential Diagnosis for Upper Back Pain under Right Scapula

Single Most Likely Diagnosis

• Musculoskeletal strain or sprain: This is the most common cause of upper back pain, often related to overuse, poor posture, or direct injury to the muscles and ligaments around the scapula. The intermittent nature of the pain and its location under the right scapula support this diagnosis.

Other Likely Diagnoses

• Costochondritis: Inflammation of the cartilage that connects the ribs to the sternum can cause pain that radiates to the upper back. The pain can be intermittent and may worsen with deep breathing or movement.
• Thoracic outlet syndrome: Compression of the nerves and/or blood vessels between the collarbone and first rib can cause pain in the upper back, especially under the scapula, along with numbness, tingling, or weakness in the arm.
• Gastroesophageal reflux disease (GERD): Stomach acid reflux can cause referred pain to the upper back, especially under the scapula, due to the shared nerve roots.
• Scoliosis or kyphosis: Abnormal curvature of the spine can lead to uneven muscle strain and pain, particularly under the scapula on the side of the curvature.

Do Not Miss Diagnoses

• Pulmonary embolism: Although less common, a pulmonary embolism can cause sudden, severe pain under the scapula, often accompanied by shortness of breath, cough, or chest pain. This is a medical emergency.
• Pneumonia or pleurisy: Infection or inflammation of the lung tissue or lining can cause sharp pain under the scapula that worsens with deep breathing.
• Myocardial infarction: In some cases, a heart attack can cause referred pain to the upper back, including under the scapula, especially in women.
• Pancreatitis: Inflammation of the pancreas can cause severe, persistent pain in the upper abdomen that radiates to the back, under the scapula.

Rare Diagnoses

• Tumors of the spine or lung: Although rare, tumors can cause persistent or intermittent pain under the scapula, depending on their location and size.
• Osteomyelitis or discitis: Infection of the bone or intervertebral disc can cause severe, persistent pain, often accompanied by fever and other systemic symptoms.
• Sickle cell crisis: In individuals with sickle cell disease, a crisis can cause severe pain episodes, including in the upper back under the scapula, due to vaso-occlusion.

Each of these diagnoses requires a thorough medical history, physical examination, and possibly diagnostic tests such as imaging studies (X-rays, CT scans, MRI) or laboratory tests to confirm the cause of the pain.