It's called Phimosis and is usually caused by a tight phimotic ring in one part of the foreskin. It's a very common problem and there shouldn't be any doctors practicing that aren't familiar with it. Due to the nature of the problem, alot of men find it difficult to seek medical assistance.
I was given a topical steroid to correct the problem. In severe cases they may recommend circumcision or mild corrective surgery.
Some Men with Phimosis run the risk of the foreskin getting stuck behind the glans which leads to Paraphimosis - where the glans will keep swelling. Paraphimosis is considered a medical emergency.
For other Men, having the foreskin retracted during its errect state can just be uncomfortable.
Either way, I recommend those with Phimosis seek medical advice because it's an easily correctable problem in alot of cases.
[This message has been edited by lightsout (edited 07-18-2003).]