Fever after stomach pain may be acute pancreatitis, acute gastritis, acute cholecystitis or gastric cancer, etc. You should go to the hospital in time to clarify the cause of the disease. 1. Acute pancreatitis: Cholelithiasis and biliary tract infections are the main causes of acute pancreatitis, while alcohol and pancreatic duct obstruction can also cause acute pancreatitis. The first symptom of acute pancreatitis is often epigastric pain, which may be mistaken for stomach pain, combined with peripancreatic infection and fever. 2. Acute gastritis: Bacteria, stress, drugs, alcohol and trauma can cause acute gastritis. Symptoms of acute gastritis vary in severity and often include stomach pain, bloating, nausea, vomiting, fever and loss of appetite. In severe cases, there may be vomiting blood, black feces, dehydration, acidosis or shock. 3. Acute cholecystitis: Acute cholecystitis is categorized into stone and non-stone. The main manifestation is stomach pain which may be accompanied by fever, nausea, vomiting and other symptoms. It can be treated according to the cause, such as gallbladder puncture under ultrasonic localization. 4. Stomach cancer: Stomach cancer may be caused by poor diet, smoking, alcohol, heredity, mental stress and so on. In early stage, stomach cancer is asymptomatic or only has slight symptoms. When the clinical symptoms are obvious, the lesions are usually in the middle or late stage, therefore, we should be very alert to the early symptoms of stomach cancer, such as stomach pain, nausea, loss of appetite, belching (burping), acid reflux, black stool, etc. If you feel unwell, you should go to the hospital in time. If you feel unwell, you should go to regular hospitals in time to avoid delaying your condition.