What Causes Pain In Rectum And Groin Area Post Testicle Removal?

My fiancé was born with an undesended (spl) testicle. He had the testicle removed and was okay for a few years. Now....everyday, constant pain in his rectum/groin areas. He's been checked every which way from Sunday by his urologist...the same doctor who removed his undesended (spl) testicle. The doctor tells us there is nothing wrong with him. I'm sorry, but being in constant pain day after day is not normal. There has to be something!! Can you please help.