Pain in the chest when the arm is exerted is mainly due to abnormalities in the thorax or sternum due to other diseases or local diseases. 1, when the arm is active, the force is transmitted through the pectoralis major muscle to the abnormal thorax or sternum, resulting in pain, common causes include acute injury to the thoracic rib cage or chronic strain. 2, seen in the upper limb activities, the force is transmitted through the pectoralis major muscle to the site of injury, resulting in irritation. When the upper limb activity, the force is transmitted through the pectoralis major muscle to the site of injury resulting in the activity of the injury site, thus stimulating the production of pain. 2, visible in the sternum or thoracic costochondritis due to the presence of costochondritis, pain occurs when the force is applied. 3, visible in lung disease or heart disease, such as myocardial ischemia, pleurisy, lung infection, etc. can also reflexively cause abnormalities in the chest, in Pain occurs when the upper limb is moved due to localized force pulling.