Pain between the right shoulder and the right chest is considered to be caused by pectoralis major muscle strain, sternoclavicular joint dislocation, thymoma, myocarditis and so on. 1. Pectoralis major muscle strain: it may be caused by muscle strain due to excessive fatigue, improper preparation activities, etc., which may trigger pain between the right shoulder and the right chest, localized swelling and other symptoms. 2. Thoracic clavicle dislocation: it can be caused by indirect or direct violence, which may show symptoms such as localized pain and swelling, accompanied by limitation of the movement of the affected shoulder. 3. Thymoma: it is a tumor occurring in the anterior mediastinum, the cause of which is still unclear and may be related to heredity. Patients often manifest chest discomfort and chest pain, mainly dull pain. 4. Myocarditis: it is an inflammatory disease occurring in myocardium, which is commonly caused by viral infection, and can also be induced by overwork, acute infection and other factors. Patients can manifest as generalized pain, sore throat, diarrhea and other symptoms. Discomfort symptoms such as chest tightness, vague pain in the precordial area and palpitations (rapid heartbeat, often accompanied by panic) may also occur. If pain between the right shoulder and the right chest occurs, it is recommended to go to the hospital in time to clarify the cause of the disease, have a comprehensive diagnosis made by a specialized doctor, and take symptomatic treatment.