What Causes Soreness And Swelling In The Testicles Post J Pouch Surgery?

my son age 28 had surgery on 2 11 2015. he has a j pouch and a colostomy bag. since his surgery he had to go back for a hospital stay about 2 weeks after surgery when the gave him antibiotics and put in a drainage tube he came back home with the drainage tube still in him, it has been over a week now and his teticals are so sore he can not sleep and one is swollen about 3 times the size of the other what could cause this?