The causes associated with vague pain under the ribs on the left side of the stomach may include gastritis, gastric ulcer, pancreatitis and other digestive disorders, as well as muscle or nerve pain under the ribs on the left side. 1. Gastritis and gastric ulcer: the left side of the stomach under the ribs still includes a part of the stomach, the patient if the hidden pain sensation, it is likely to be related to stomach diseases, such as gastritis, gastric ulcer and other diseases. Chronic gastritis to hidden pain, distension as the main performance, when the food on the stomach wall caused by the stimulation, the patient will also be accompanied by the left side of the ribs under the hidden pain feeling. Gastric ulcer patients may experience a vague pain or cramping pain on the left side of the lower edge of the ribs, and the pain usually worsens after eating. 2. Pancreatitis: The pancreas is located in the left upper abdomen, and when there is pancreatitis, there will also be pain under the left side of the ribs, which may be vague pain or severe pain, and may be accompanied by pain radiating to the back. 3. Subcostal muscle or neuralgia: If the left subcostal muscle or fascia is damaged, it will also be manifested as left subcostal pain, which is commonly seen in frequent stooping activities or long-time workers, which will easily lead to muscle pulling injury, thus causing pain in the left subcostal muscle and fascia of the stomach. In addition, patients with left intercostal neuralgia or inflammation of the rib cartilage may also have symptoms of subcostal pain. It is recommended to go to the hospital for examination to identify the cause of the pain.