What Causes Throbbing Pain In Testicles When Treating UTI?

I am a 27 yr old male. About 2 wks ago I was treating for a UTI. I took antibiotics and it cleared up. Then my testicles began to have this throbbing pain. I have been to the ER 3x and to the doctor 3x. 2 of them were urologist who couldn t tell me why I was having this pain. Today I had a uroscopy and they dilated my bladder. I still have no relief. I am taking anti-inflammatories and on pain meds which don t really cut the pain. What is wrong with me?