Hi.. Phimosis if it is causing problems with urination or sexual activity can only be treated with surgical treatment. And yes the surgical treatment is the circumcision.. Circumcision is the only treatment. It is a simple surgery and the common side effects are bleeding and infection which is part of any surgery which would be taken care of...
Circumcision isn't the only treatment. Try steroid creams and stretching first:
http://www.norm-uk.org/circumcision_alternative_treatments.html