Was your phimosis diagnosed by a doctor? If you have not been to a urologist yet, please go. He will be able to diagnose what is causing the itching and whether or not you actually have phimosis.

Phimosis is pretty easy to spot. I currently have it. If your foreskin doesn't retract over the head, that's essentially it. It can be painful in some cases. I'm not sure what the itching might be about. There's a possibility that you may have some fibres (pubic hair or material) trapped behind the foreskin. I would get it checked out staight away if it was causing irritability.

If you're young however and still going through puberty, your foreskin isn't supposed to retract. Phimosis isn't something that can really be diagnosed until you're done with puberty, unless the ring at the foreskin tip is really, really tight.