Since the shoulder joint is the joint with the largest range of motion in the human body and also the joint most prone to injury, the incidence of chronic pain in the shoulder joint is high and bothers the general public, especially middle-aged people around 50 years old. Once the shoulder joint function is impaired, the patient’s daily life and work will be seriously affected, and the quality of life will be reduced. Because it is very difficult to diagnose and differentiate shoulder pain, doctors who do not have expertise in shoulder joint often diagnose shoulder pain as “frozen shoulder” in general, so that the diagnosis of “frozen shoulder” is a household name. This is why many people who experience shoulder pain and restricted movement think they have frozen shoulder (medically known as “adhesive capsulitis”, commonly known as “fifty shoulder”). Shoulder joint diseases are common in clinical practice and are mainly caused by degenerative strain and trauma to the shoulder joint, including rotator cuff injury, subacromial impingement, shoulder instability, and frozen shoulder. Rotator cuff injury is a degenerative disease that accounts for about 40% to 50% of shoulder pain patients and has a higher incidence in the elderly. The rotator cuff is a dynamic and stable structure of the shoulder joint, consisting of the supraspinatus, infraspinatus, subscapularis and teres minor. Functioning as a whole, it rotates the upper extremity and stabilizes the humeral head and glenoid together. Rotator cuff injury is mainly characterized by shoulder pain, weakness in lifting, resting pain, waking up at night with pain, and inability to lie on one’s side. Subacromial impingement syndrome: It accounts for about 20% of patients with shoulder pain. The subacromial impingement syndrome is a group of clinically common diseases that cause shoulder joint pain and activity disorders, with inflammation and injury to the rotator cuff, biceps tendon and other structures as the main pathological changes. When the shoulder is lifted or externally rotated, the rotator cuff, bursa, ligaments and other soft tissue structures between the shoulder peak and the humeral head are subjected to repeated impact and friction, causing inflammation and injury. The main manifestation is chronic dull pain in the shoulder, which is aggravated during supination or abduction activities. In this case, an X-ray of the shoulder joint should be taken to show that the curved and hooked shoulder crest is the cause of subacromial impingement. Patients need to reduce shoulder extension, overhead lifting, and other exercises, along with pharmacological anti-inflammatory and analgesic treatment. Some patients also need minimally invasive arthroscopic surgery to eliminate the causative factors of subacromial impingement. Shoulder instability: About 10% of the patients with shoulder pain have repeated dislocation or subluxation of the glenohumeral joint, of which the anterior instability accounts for 95%, mainly manifesting as shoulder pain and fear of movement in a certain direction of the shoulder joint. Shoulder joint X-ray shows: shoulder dislocation, shoulder MRI shows: injury to the anterior inferior glenoid lip of the scapula, etc. Frozen shoulder: about 5% of the patients with shoulder pain, mainly due to shoulder pain and limited active and passive activities. The incidence of true frozen shoulder is not high, but refers to aseptic inflammation of the shoulder joint muscles, tendons, ligaments, joint capsule, and other soft tissues, resulting in congestion and edema, which can cause adhesions in severe cases. Patients often feel that the joint is stiff and the arm is restricted in its backward and outward rotation, which affects their daily life as if they are frozen, hence the name “frozen shoulder”. In addition to the above diseases, subacromial bursitis, long head biceps tendinopathy, long head tendon dislocation, calcific supraspinatus tendinitis, rostral impingement, acromioclavicular joint disease, thoracic outlet syndrome, etc. can cause shoulder joint pain. Both patients and doctors should pay attention to shoulder pain and carefully identify the specific causes of shoulder pain, and should not treat it blindly.