I'm not masturbating any more and i'm not having sex, but sometimes, after i've been playing around with my gf, my testicles hurt. its hapenenin often?

Blue Balls: "blue balls" is a colorful slang term for the condition of temporary vascular congestion in the testicles accompanied by testicular pain/discomfort caused by prolonged sexual arousal without ejaculation. When a man becomes sexually excited, the arteries carrying blood to the genital area enlarge, while the veins carrying blood from the genital area are more constricted leading to vasocongestion.