What Could Be Causing A Double Stream And Painful Urination With Blood In Urine?

Hello, I recently noticed that I have double stream and a painful urination..so I went to the hospital for urine test..the test result showed that I didn’t have any UTI however blood was visible in the urine..I was sent for renal ultrasound and everything came out fine…so please what could be the possible cause of the blood in the urine?