There are many causes of pain under the left side of the chest in women, and there are common cardiogenic diseases, pleural lesions, digestive diseases, breast diseases, chest wall diseases and so on. 1. Cardiogenic diseases: coronary atherosclerotic heart disease, heart failure, arrhythmia and other diseases can lead to myocardial ischemia, resulting in pain under the left side of the chest, the nature of the press-like, pinch-like, stuffy pain, the throat can be constricted. The pain may radiate to the back of the left shoulder, and in mild cases, sublingual coronary artery expansion drugs such as nitroglycerin can relieve the pain. 2. Pleural lesions: when various kinds of pneumonia involve the pleura and pleurisy occurs, with the pulling of the pleura by respiratory movement, it can produce pinprick pain on the left side of the lower chest. 3. Digestive diseases: gastritis, reflux esophagitis, peptic ulcer and other digestive diseases, in addition to acid reflux, heartburn, belching, appetite reduction and other manifestations, but also the left lower chest pain. The pain of peptic ulcer is often regular, gastric ulcer is mostly pain after eating, duodenal ulcer is often manifested as hunger pain, night pain, etc. Usually, taking proton pump inhibitors such as omeprazole, gastric mucosal protective agent colloidal bismuth pectin can relieve. 4. Breast diseases: Commonly, there are breast cancer, breast hyperplasia and other diseases, local nerve involvement can also cause pain under the chest. 5. Chest wall diseases: such as costochondritis, boils on the chest wall can cause localized pain, the localization is often clearer, and the nature of the pain is also clearer. When the left side of the lower chest pain is urgent for heart-related diseases, it is recommended to consult the hospital in time to clarify the cause of the disease and then targeted treatment.