Sore breasts experiencing leakage from the nipples 16 months after delivery could be due to an infection or hormonal imbalance (excessive prolactin, for example) but it is very important that the breasts are examined (inspection and palpation) by your GP or your gynecologist. Further diagnostic procedures (mammography, ultrasound, hormonal analyses) can be done if necessary. You are probably not pregnant if you haven’t missed your period yet but you may take a pregnancy test to be sure.