What is causing the pain when I urinate during my period?

I'm a 32-year-old woman, and two years after giving birth to my twins, I began experiencing pain in my genital area when urinating. The pain starts on the first day of my period and lasts for about two weeks, persisting even after my period ends. This cycle repeats every month when my period begins.

I have consulted multiple doctors, but none have been able to diagnose my condition. My test results confirm that I do not have a urinary tract infection, and my kidneys, bladder, and ovaries are all healthy. Ultrasounds and other tests have also ruled out endometriosis. I have no other symptoms apart from this recurring pain, which is deeply concerning. Despite my distress, doctors have only recommended painkillers.