Adhesive Capsulitis (Frozen Shoulder): This condition is characterized by pain and stiffness in the shoulder joint, which can lead to a sensation of clicking or grinding. The pain can also radiate to the neck on the same side, fitting the patient's symptoms.

Rotator Cuff Tendinitis: Inflammation of the tendons surrounding the shoulder joint can cause pain, especially when moving the arm, and may lead to clicking sensations due to tendon impingement.
Subacromial Bursitis: Inflammation of the bursa that cushions the rotator cuff tendons can cause pain and clicking in the shoulder.
Cervical Radiculopathy: Compression or irritation of the nerves in the neck can cause pain that radiates down the arm and may be accompanied by neck pain on the same side.

Thoracic Outlet Syndrome: Compression of the nerves and/or blood vessels that pass into the arm can cause pain, numbness, and tingling in the arm and hand, and sometimes a clicking sensation due to the compression of structures.
Cervical Spine Fracture or Dislocation: Although less common, a fracture or dislocation in the neck can cause severe pain and neurological symptoms, including arm pain and numbness.
Pancoast Tumor: A type of lung cancer located at the top of the lung can cause shoulder and arm pain due to invasion of the brachial plexus, a group of nerves that come from the spinal cord.

Osteonecrosis of the Humeral Head: A condition where the blood supply to the bone tissue at the head of the humerus is interrupted, leading to bone death and potentially causing shoulder pain.
Septic Arthritis of the Shoulder: A bacterial infection within the shoulder joint, which is rare but can cause severe pain, swelling, and limited mobility of the shoulder.
Brachial Plexitis (Neuralgic Amyotrophy): An inflammatory condition affecting the nerves of the brachial plexus, leading to severe pain in the shoulder and arm, followed by weakness and atrophy of the muscles.