lunaticred

I'm a 20 year old guy, uncircumsized. My foreskin is tight around the glans of my penis, I can pull it down when I'm erect, but only about halfway before it gets rather uncomfortable. With lube it goes a little further. Does anyone have any suggestions? I'm afraid that having sex with my girlfriend will be uncomfortable because of it. Besides that, my doctor made mention when I was getting a physical once that I should try to stretch it, but gave no indication how. Any advice?