Vague pain below the left chest in women can be seen in lung disease, coronary heart disease and stomach disease. Pneumonia involving the pleura can cause chest pain related to breathing. Patients often have increased chest pain when inhaling deeply, coughing and turning position, and the chest pain decreases or disappears when holding the breath. The lower left vague pain is mostly seen in lower left pneumonia, pneumonia is often close to the pleura, so it is manifested as chest pain, and also accompanied by fever, cough, cough and other symptoms, it is recommended to do chest X-ray or lung CT for clear diagnosis; second, coronary heart disease, coronary heart disease includes angina pectoris and acute myocardial infarction. It is recommended to do electrocardiogram and myocardial enzyme spectrum examination to clarify the diagnosis; third, stomach diseases, when patients have gastritis and gastric ulcer, they will have pain under the left chest, accompanied by nausea, vomiting, acid reflux, belching and other symptoms, it is recommended to do gastroscopy to clarify the diagnosis.