There are many reasons for vague pain below the left rib, such as digestive system lesions, lung lesions, heart disease, intercostal neuritis and diaphragmatic spasm. 1. Digestive system lesions: esophageal lesions, gastritis, gastric ulcer and other diseases, due to gastroesophageal reflux, which leads to an acute attack of the phenomenon of hidden pain under the left rib. 2. Lung lesions: Pneumonia, lung cancer, tuberculosis and other diseases, will also appear in the phenomenon of hidden pain below the left rib, accompanied by coughing, coughing up sputum and other symptoms. 3. Heart disease: pericarditis, coronary heart disease and other diseases, pericarditis due to pericardial mucosa inflammation exudate stimulation; coronary heart disease due to coronary artery lesions, the heart reduces the supply of blood, will cause pain in the anterior region of the heart, so that the patient feels a vague pain below the left rib. 4. Intercostal neuritis: intercostal neuritis is mainly due to the inflammatory reaction of the costal cartilage tissue and intercostal nerves, which leads to local tissue pain, especially after changing the position. 5. Diaphragmatic spasm: long time running, sports, emotional excitement and other behaviors may lead to accelerated respiratory rhythm, resulting in diaphragmatic spasm, which will lead to hidden pain below the left rib. Causes of hidden pain under the left rib is very many reasons, it must pay attention to it, we recommend that patients go to the hospital in a timely manner to improve the examination, identify the causes of the standardized treatment, to avoid delay in the diagnosis and treatment of the condition.