What Causes Severe Pain On Penis Shaft?

My brother had a sex reassignment surgery at birth due to indeterminate sex organs. When he was 12, he sustained an injury to his penis that caused difficult urination and inability to completely evacuate the urine. Over the last month and a half, he has begun to experience pain in the penile shaft that is extreme with touch and lasts several seconds after contact. There is also pain when it is not touched that is significantly reduced when large amounts of water are ingested. He asked me for help because I love medicine, but I m not very familiar with men s issues. He has no medical insurance, and his minimum wage job doesn t cover doctor bills. Any ideas? Thank you!