Stinging pain in the urethra after urination during menstruation is usually caused by a urinary tract infection, most likely caused by acute cystitis. Acute cystitis usually has a sudden onset, there will be obvious urinary frequency, urgency, urinary pain, burning sensation in the urethra during urination, and the bladder area at the end of urination may have crushing discomfort. If these symptoms occur, it is best to check the routine urine test to see. If there is an increase in the white blood cell count in the urine routine, it is considered to be an infection of the urinary system, which can be treated with oral antibiotics, such as levofloxacin, cefixime, or fosfomycin aminoglutethimide, usually for about 3-5 days. Usually drink more water, urinate more, eat less spicy and stimulating food, keep the perineum clean and hygienic, if breastfeeding, stop the medicine for 3 days before you can continue to breastfeed.