The main causes of arm muscle pain in postpartum women include postpartum weakness without timely nutritional supplementation, accumulation of acidic metabolites in the body due to excessive local exertion during delivery, and muscle strain caused by holding the baby for a long time after delivery. You can take the following ways to relieve: pay attention to more rest after delivery, at least one month before you can carry out appropriate physical labor. Appropriate increase in nutrition, you can eat more food rich in high protein and vitamins. Postpartum can carry out appropriate rehabilitation exercise, for the sore parts can be taken to hot compresses and massage to ease the way. When the pain is more obvious, you can go to the hospital to do some physical therapy. In addition, it should be noted that six weeks after delivery, you need to go to the hospital for a routine examination.