Im 15 and my foreskin can only retract a little bit when soft or erect

The sensitivity is normal because it's not getting exposed.

Is it not going back because the opening in the tip is too small? If so you need to stretch the opening. You can do that by inserting your two little fingers and stretching it open. The best time is while you're in the bath or shower and it's wet and warm so it stretches more easily. If you cannot get two fingers in there another way is pulling it back when it's erect. Hold it tightly stretched for several minutes each time so it slowly stretches.open. Do it as often as you can and it should go back over the glans in a few weeks. You will probably have to do this quite often afterwards to keep it from shrinking back to being tight. That should be easy to do if you pull it back constantly while masturbating because it will feel so good you will want to keep doing it. As for the sensitivity, after you are able to expose the glans just keep touching it as much as you can and it will get used to being touched. That's another thing that will feel so good you will want to do it a lot.

Hey there I agree with njoy. If the skin is too tight you have phimosis which is a fairly common condition and often can be cured with gentle stretching exercises and sometimes steroid cream. Do you feel the opening of your foreskin is too small to pull back or is your foreskin literally stuck to the glans (head) of your penis?  And as  for penis size, when did you start puberty ? As you continue through puberty your penis should get bigger so don’t worry about that....

So when im like really soft I got the foreskin almost a the way back over the head, but then I start getting an erection and it gets really tight and so I have to roll it back forward fast

so when I'm erect I can't really pull it back much, and also my penis isn't big enough that I can put my hand and pull the foreskin down that far, like idk how to explain it but when I'm masturbating I can't pull my foreskin down that much, because of the size of my penis

So for now I just get erect and hold it there for 2-3 minutes pulled as far down as I can before it hurts

Hopefully this stretches it enough that I can pull it down erect, and hopefully my penis grows more cause I started puberty around when I was 12 and I feel like my foreskin length is too big for my actual penis size, idk

 So what you described makes sense have you ever tried soaking in a bath with Epsom salt before stretching your penis? I would try stretching your penis when is partially erect if you can and then as your foreskin get looser you can stretch with a full erection. The biggest thing that you want to happen is always make sure your foreskin goes back over your glands and it doesn’t  and it doesn’t get stuck behind the head of your penis. You may need to use some lube to help you with that. Taking your time and stretching should allow you to eventually easily pull back your foreskin those with any reaction and one soft. As for puberty and your penis size. How big is your penis soft And erect? If you have a hard time complely retracting your foreskin with your hand due to your penis size you can try just grabbing onto your penis with two or three fingers and sliding your foreskin down that will give you more room. And how big are your testicles? And what other secondary sex characteristics do you have like pubic hair armpit hair facial hair etc. has your voice gotten deeper? Also are you overweight at all? 

Thanks

soft my penis is like 2in hard like 5in my testicles are a bit smaller than a grape maybe and I have a bit of armpit hair alot of pubic hair and my voice has gotten a bit deeper but it's still a small bit high. And im not overweight if anything abit skinny