Im 16 and, 3 days ago I tried masturbating (which i do around once every 2-3 days) and i couldnt EJACTULATE! AT ALL! I usually last 6-10 minutes but, this one lasted 30 MINUTES! This happened again today and im concered. i start to feel like it might be coming, but it doesnt even get close. Also, my left testicle hurts during mastutbation *just those 2 times*. why is this happening?