The common causes of left chest pain are mainly as follows: a. Older female patients may suffer from left breast malignant tumor invading into the chest wall and muscles, causing left chest tugging pain. At this time, patients can improve mammography ultrasound, magnetic resonance, mammography and other examinations to clarify the nature of the lesion and perform mastectomy for malignant tumor as soon as possible. After surgery, combined with local radiotherapy, systemic chemotherapy, endocrine therapy and other comprehensive treatment, effectively reduce the left side of the chest pain. Second, the fracture of the left rib can cause intercostal nerve injury, accompanied by left-sided chest pain. At this time, patients can improve the CT or X-ray examination of the ribs to clarify the severity of rib injury. Internal or external fixation of the ribs should be performed as soon as possible, and the left-sided chest pain can be gradually relieved after repairing the rib fracture.