Why would my right testicle hurt?

Many reasons: Torsion (/"twisting") of the testicle or its appendix; local trauma; epididymitis or other infection; other causes of swelling; tumor...Sorry there are a lot of potential causes. If pain intensifies, can indicate an emergency. Best to get it checked out--urgent care or er if severe (also er can usually get ultrasound to evaluate it).

See doctor: Could be an infection or a testicular torsion among other causes.If it is a torsion this is a medical emergency so see a doctor now.

Testis pain = see Dr: Testicle pain means a trip to the doctor right away because the testicle's blood supply can be twisted off (called torsion). When that happens, the testicle can die. Other causes of testicle pain include trauma, infection, twisting of an appendix of a testicle (a small lump next to a testicle), etc... Since one usually cannot tell if his testicle is twisted, an exam by the doctor is needed.