For three months postpartum lying down to sleep back pain, generally and postpartum hormonal changes caused by ligament and lumbar muscle strain, relaxation, postpartum holding the child, breastfeeding, care of the child to sleep, etc. is also more fatigue, while the posture will also be inappropriate, it will cause pain, but also in the process of pregnancy and production of long-term activities to reduce the strength of the lumbar muscles weakened, while the weight of the pregnancy increases, the burden of the lumbar region is also relatively large, the lumbar muscle will cause strain, and both cesarean section or normal delivery have a certain damage to the lumbar muscle, thus producing pain. The lumbar muscle will cause strain, and both cesarean section and normal delivery have some damage to the lumbar muscle, generally recovering from the lumbar muscle strength is not enough, thus producing pain, meet the labor, cold easily aggravate the pain. Other than muscle tension, fasciitis leading to lumbar pain, you also need to pay attention to whether there is a poor post-partum recovery, inflammation, or previous disc herniation, other internal diseases, such as gastrointestinal inflammation, kidney disease and other causes of pain. If there is such a condition, there will be other manifestations, after checking clearly to treat the symptoms.