My last period was April 30,2013 since then my breast are really sore could I be pregnant

If you had sexual intercourse since April 30 yes you could be pregnant. But it is too soon for symptoms to manifest themselves. The first discernible symptom is a missed period.

Normally there are no "signs" before you miss a period, sore breast could be many things.

Wait till you miss your period, you need to be 2 weeks late, then do preganncy test, with first urine of the morning