If you had sex 7-10 days after your last period you could be pregnant. Did you check a pregnancy test about a week after your last period. Anyway, your breasts usually won't become sore until farther into your first trimester but there are some women who get that feeling earlier. Give it a little more time and you just may get that awful pain. Maybe you will be one of the lucky ones and not have to go thru that until later on or at all.
