Pain on the right side of the chest can be caused by the following diseases: First, chest infection, lung tissue infection, the patient will have chest pain along with cough, sputum and fever, usually after effective anti-infection treatment, the pain symptoms can be gradually reduced. Secondly, malignant tumors occurring in lung tissue, the typical symptoms are chest pain accompanied by coughing with blood, and CT examination can find obvious occupying changes. If the wall pleura is involved, the patient’s painful symptoms will gradually worsen and neck discomfort and numbness will appear, and patients with early diagnosis should choose surgery in time. Thirdly, some patients are caused by breast enlargement, usually with breast swelling or chest discomfort, and also shoulder and back pain. Ultrasound examination can confirm the diagnosis, and this disease is more often seen in middle-aged women, and is related to degenerative changes in the mammary glands, and is also affected by the hormone level in the body.