I took plan b 10 days ago, my period is due in 13 days but my boobs are sore now is that normal?

Hard to tell...: It can be hard to tell if a woman is pregnant because some of the symptoms seen in early pregnancy can also happen in non-pregnant women. A urine pregnancy test gives a reliable result. Generally, one can test about 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. Also, a woman should always check a pregnancy test 3 weeks after using Plan B.