I am uncircumcised and when erect the foreskin does not retract past the head but sits about on the bottom of it. I have been masturbating quite often lately and I think it could be related. I have a red area on the head which I noticed which just seems to of appeared. It stings quite a lot but not when urinating.
If it helps, my penis is 4.2 inches when erect and 2 inches when flaccid.
If anyone could help that would be great because I am quite worried.
Delete the link to your picture - NOW.
It's NORMAL for your foreskin to not retract until around age 16 or so. You need to stretch it. You can get an erection and pull down on the shaft skin so that the glans spreads the opening OR you can use your fingers. Do it in the shower, the warm water helps soften the skin. The more often you do this the sooner you'll be able to easily slide your foreskin.
The glans will be very sensitive at first, even somewhat painful. It'll reduce in time.
Have you cleaned under your foreskin? It can be difficult and a bit painful to clean if you can't retract your foreskin. You'll likely find a lot of smegma and that is probably part of the cause of the redness.
Your penis is a bit bigger than average for a 13-14 year old, 3-4".
You are very NORMAL sir.