The monthly did not sit well back pain may be cold, lumbar muscle strain, sedentary and other reasons, at this time you can through adequate rest, hot compresses, physical therapy and other methods to solve. 1. Cold: If the lumbar region is cold, the local blood circulation is not good, the muscles are more tense, the symptoms of lumbar pain will occur, at this time you should pay attention to warmth, the use of hot compresses and other methods to promote symptomatic relief. 2. Lumbar muscle strain: if the patient because of pregnancy leads to excessive pressure on the lumbar muscle, lumbar muscle strain, will also be manifested as lumbar pain after menstruation, at this time you can massage, microwave and other physical therapy treatment, to promote symptomatic relief. 3. Sedentary: some patients in a sedentary position for a long time to feed the child, may also cause back pain. At this time, you should avoid sitting or standing for a long time, and it is recommended to change the position of breastfeeding, which will also relieve the symptoms. Low back pain after the month may also be the cause of lumbar disc herniation, etc. It is recommended to go to the hospital in time when the symptoms occur, under the guidance of the doctor, standardized treatment, to promote symptomatic relief.