Why is my foreskin stuck on the head?

Para phimosis . This occurs when the foreskin of an uncircumcised male cannot be pulled back over the head of the penis. This can lead to swelling and pain. There is a ring in the foreskin called phimotic ring that can act as a fibrotic ring and may not stretch. Once behind the head of the penis, it can choke on it (ie like chocking the chicken). You need to see an md, preferably a urologist.