Lumbar pain during breastfeeding, the reasons are as follows: a. One side of the lumbar muscle strain: mostly caused by poor breastfeeding posture, such as often unilateral breastfeeding, which will make the lumbar bilateral force imbalance, may cause one side of the lumbar muscle strain. It is recommended that women alternate breastfeeding, breastfeeding time as short as possible, do not take too long, otherwise it is easy to cause muscle strain. Carrying a child for too long is a weight-bearing activity, which can cause an increase in the load on the lumbar muscles, resulting in strain on the lumbar muscles, manifesting as soreness and pain in the lower back. During the breastfeeding period to carry out functional exercises for the lumbar muscles, while trying not to hold the child for too long, you can also use local heat compresses, massage, etc., to relieve pain and muscle stiffness.