The pain doesn't occur often, and I can't remember the last time it happened, but today I was working out doing relatively heavy squats, 285 5x5 for what it's worth, and on my last set and last rep I felt an extremely sharp stabbing pain. I was struggling on this last rep, what could have happened? I've had Chlamydia in the past (nearly a year ago) and had that treated... all is good; however, I'm very worried about STDs - almost in a hypochondriac fashion.