I know breast soreness is common before a period, i've never had that before and for the past few days my nipples/breast have been swollen and sore?

Nipple pain: Hormonal fluctuations, medication changes. weight gain and poorly fitting bras are common cause of nipple pain. Jogging or recent exercise changes can cause the nipples to rub. Schedule a visit for an exam if none of these apply to you. If you think you might be pregnant check then check a home pregnancy test. They are cheap, reliable and available at any pharmacy.