Differential Diagnosis for Pain in Back of Neck Radiating to Back of Left Shoulder

• Single Most Likely Diagnosis
  • Cervical Spondylosis or Cervical Disc Herniation: This condition is a common cause of neck pain that radiates to the shoulder due to compression or irritation of the cervical nerve roots. The pain pattern and radiation to the shoulder are typical for this diagnosis.
• Other Likely Diagnoses
  • Musculoskeletal Strain: Overuse or acute injury to the muscles and ligaments in the neck and shoulder region can cause pain that radiates from the neck to the shoulder.
  • Thoracic Outlet Syndrome: Compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib) can cause neck and shoulder pain.
  • Rotator Cuff Tendinitis or Bursitis: Inflammation of the tendons or bursae in the shoulder can cause pain that is referred to the neck.
• Do Not Miss Diagnoses
  • Cervical Spinal Stenosis: Narrowing of the spinal canal in the neck can compress the spinal cord, leading to serious neurological symptoms if not addressed promptly.
  • Vertebral Artery Dissection: A tear in the vertebral artery can lead to a stroke, making it a critical diagnosis not to miss, although it is less common.
  • Lung Tumor (Pancoast Tumor): A tumor in the apex of the lung can cause shoulder and neck pain due to invasion of the brachial plexus and adjacent structures.
• Rare Diagnoses
  • Rheumatological Conditions (e.g., Rheumatoid Arthritis, Psoriatic Arthritis): These conditions can cause neck and shoulder pain but are less common causes of the specific pain pattern described.
  • Osteomyelitis or Discitis: Infections of the bone or disc in the cervical spine can cause severe pain and are medical emergencies, though they are rare.