How Can Foreskin Tightness Be Treated?

Hello I am 18 years old male and I am a virgin and I am also uncircumsized. I masturbate a lot and when I masturbate I usually do not pull my foreskin all the way back I just let the foreskin stay on the top of the penis head and masturbate. Recently I decided to pull my foreskin all the way back to masturbate the problem is that when I pull my foreskin behind the penis head while I have erection there is a little tightness around the "neck" of the penis I can still pull in and out the foreskin but when I ejaculate I feel like the sperm is trapped and it's more hard for me to ejaculate. Please help.