Can doctors tell me what does this mean when you have pain in lower abdomen while breastfeeding?

Uterus contracting: One of the hormones you produce while breastfeeding can also cause uterine contractions. These are most prominent right after giving birth when the uterus is enlarged, but can occur at any point while breast feeding because the uterus is just a big muscle that is sensitive to that hormone. The bright side is that the breast feeding helps get your uterus back to normal size and in shape!