Girls appear left side of the chest hidden pain causes: 1, must consider whether there are heart problems, such as acute myocardial infarction or angina pectoris. In addition to vague pain, and the nature of the pain is mainly to squeeze the feeling of the main, and accompanied by chest tightness, palpitations or dizziness, cold sweat, etc., you can go to the hospital to check the electrocardiogram and blood troponin, basically to confirm the diagnosis. 2, there may be a breast problem, the breast of the swelling, such as breast hyperplasia, fibroid tumors, serious or even cancer of the breast may be localized. 3, there may be thoracic rib arthritis, usually caused by aseptic inflammation of the joints between the sternum and the ribs, usually related to breathing and movement. When you take a deep breath or thoracic activities, the pain will appear or aggravate.