Take your phone and if you still have your receipt to where you bought your phone from. If they can't help you then call up the phones company. You need to provide evidence though, they might think it's a stollen phone. They'll tell you what to do anyways.
Call your service provider and they'll give you your PUK (that's the british one but you'll have something similar). Get your pin wrong enough times that it locks itself, then use the PUK and it'll ask you to reset your pin. Hope this works
Try the last four digits of your number. If it's not that then flip through the booklet it came with, it will tell you somewhere in there.
Take the phone to your provider and they should be able to help you out.