The causes of left subcostal pain in a 50-year-old woman are: trauma, breast disease, rib disease, respiratory disease, heart disease and so on. 1. Trauma: impact on the left side of the ribs or fracture of the ribs will lead to hidden pain under the left rib. 2. Breast diseases: such as mastitis, breast hyperplasia and breast cancer. 3. Rib diseases: such as herpes zoster, costochondritis, costal neuritis under the left rib. 4. Respiratory diseases: such as left lower lung contusion, left lower lung pleurisy, etc. 5. Heart diseases: such as myocardial infarction, coronary heart disease, angina pectoris and so on. 50-year-old woman left under the ribs hidden pain, need to go to the hospital in time for related examinations, such as chest X-ray film, ultrasound, etc., to clarify the cause of the disease, targeted treatment.