If the patient has pain in the left side of the abdomen with fever and other symptoms, the possibility of pyelonephritis should be considered. 2. If the left side of the abdomen is painful, but there are symptoms such as frequent urination, urinary urgency and painful urination, it may be caused by acute cystitis. 3. If the pain in the lower abdomen is severe, accompanied by hematuria and percussion pain of the kidneys, the possibility of ureteritis or kidney stones should be considered. 4. If the left abdominal pain is accompanied by fever, it may be due to pelvic inflammatory disease or tubal inflammation; if the left abdominal pain is accompanied by a mass, it should be considered as ovarian torsion or corpus luteum rupture. The above are some of the causes of vague pain on the left side of the abdomen. It is recommended that patients should go to a regular hospital for relevant examinations to clarify the specific disease and then treat it symptomatically.