There are three main reasons for pain in the pectoral muscles, 1, due to lifting and carrying heavy objects, excessive force exceeds the normal load on the muscles, there will be muscle strain, which will form local bruising and inflammatory edema, stimulation of peripheral nerves around the pain, and in the muscle force and passive pulling, the location of the lesion is further stimulated, the symptoms of pain aggravated. 2, due to The pain will also occur due to the frequent muscle contraction, which leads to muscle fatigue, long-lasting strain and inflammatory lesions in the pectoral muscles, stimulating the surrounding tissues and structures. 3. After that, the situation of cold should never occur, because after the cold will become more muscle tension, blood circulation will also slow down, after the slowdown of venous return will lead to the accumulation of inflammation and further aggravation of pain.