Not as severe as a shot to the crotch, but pretty close. Sometimes accompanied by swelling.
The condition: Odds are it's something called testicular torsion. Normally, a man's testicles are attached to his body in two ways: by the spermatic cords, which run into the abdomen, and by fleshy anchors near the scrotum.
But sometimes, in a relatively common congenital defect, these anchors are missing. This allows one of the spermatic cords to get twisted, which cuts off the flow of blood to the testicle.
"If you catch it in 4 to 6 hours, you can usually save the testicle," says Jon Pryor, M.D., a urologist with the University of Minnesota. "But after 12 to 24 hours, you'll probably lose it."
Another possible cause of the pain in your pants: an infection of the epididymis, your sperm-storage facility.
The diagnostics: A physical examination, possibly followed by an ultrasound. Antibiotics can stifle an infection. And if your testicles are doing the twist? A surgeon will straighten the cord, then construct artificial anchors with a few stitches near the scrotum.
