A slight pain during breast milk feeding is completely normal as the nipple gets sucked by the baby. But the pain and discomfort goes away after the first minute as you get eased into it. But if the pain persists and you have a painful experience every time you breastfeed and soreness around the nipples then you may have mastitis. It is an infection of the milk ducts. Get your self checked by the doctor if you have mastitis immediately. But the good news is that you should continue breastfeeding as it helps in clearing up the infection. Other possible factors include sore breasts which is quite common. This is because the ducts have become clogged. You should take warmer showers and massage your breasts gently but firmly multiple times a day.