Frequent vague pain inside the ribs on the left side of the left thoracic cavity may be caused by costal neuralgia, pleurisy, heart disease and other reasons. 1. Costal neuralgia: if the patient’s thoracic spine has degenerative disease, thoracic spine injury, tumor and other diseases, the intercostal nerves will be stimulated or compressed by the above diseases, which will cause local inflammatory reaction and lead to swelling, pain and other symptoms. 2. Pleurisy: If the pleura is infected by viruses, pleurisy will be induced, which will cause the patient’s body to show unhealthy signals, such as chest pain, which will make the patient show that the left thoracic cavity is partial to the left side of the ribs inside the often hidden pain. 3. Heart disease: heart disease will lead to problems with the heart and structure and the heart conduction system, resulting in symptoms such as tachycardia and atrial fibrillation, which will also cause the patient to experience frequent vague pain in the left side of the left chest cavity and left side of the ribs. It is recommended to go to the local regular hospital to do chest CT, MRI, ECG and other related examinations, according to the results of the examination to clarify the causes of chest pain, under the guidance of the doctor for symptomatic treatment.