itchy nipples is not a confirmatory sign of pregnancy.. in fact it might be due to dryness even.. if you are very uncomfortable and are experiencing some more changes and have also missed a period and you doubt that u might be pregnant you can go for a pregnancy test..that shall confirm it.. good luck..
You did not give much information other than You doubt You could be to go by but I am sure if You were pregnant You would be experiencing more than Your breasts itching and being sore, is it possible You have had an allergic reaction to a product you have used
When was your last period