It is recommended to go to the hospital for an examination to clarify the possible causes. 1, cystitis is the most common cause, when cystitis occurs it can lead to pain in the small abdomen when urinating, accompanied by frequent urination, urinary urgency or cloudy urine, bleeding urination, etc. It may also be accompanied by back pain or increased body temperature. It is necessary to carry out further cystoscopy and routine urine tests to further clarify the presence of cystitis. 2. bladder stones, when there are stones in the bladder, stones flowing with urine can cause bladder irritation and pain, and symptoms of hematuria can also occur. Some patients may experience interruptions in urination and need further urological ultrasound or abdominal X-ray to see if stones are present. 3. Bladder tumors can cause local destruction of the bladder mucosa or invasion of the bladder muscle layer. This can be characterized by vague pain in the small abdomen or increased pain in the small abdomen during urination, and may be accompanied by the manifestation of hematuria in the naked eye, which requires further CT or cystoscopy of the urinary system to rule out.