If the patient is over 40 years old and has frequent occult pain in the small abdomen, it may be caused by colon tumor, such as cecum tumor or sigmoid colon tumor, rectal tumor, etc. The patient will have occult pain in the lower abdomen, and will have more frequent stools, thinner stools, black stools, bloody stools, etc. If necessary, colonoscopy or CT examination of the left abdomen can be done. If the patient is young, it may also be caused by small intestine spasm, especially after the abdomen is cold or eating fatty food, manifested in the navel, lower abdomen with vague pain, paroxysmal pain, etc., which can generally improve after rest or massage. It is also possible that the lesion is caused by chronic appendicitis, mainly in the right lower abdomen with vague pain, usually with a history of acute appendicitis attack before, and the condition improves after conservative treatment, you can perform appendix ultrasound or barium enema for diagnosis.