After going poop, my husbands right testicle hurts real bad, what could cause this?

Don't know anything about this subject. I do suggest you don't hesitate to ask a doctor right away. In fact, going to the emergency room would not be a hasty decision.

It may be just a one time thing also is this the first time this has happened? I'm a man and I've had my testicles hurt before from going pee and force stopping the flo, he could also have a hurnia

My husband thinks it's a hurnia. Go get checked out.