There are two common causes of chest pain caused by arm movement: 1. Soft tissue contusions of the chest, usually related to trauma, are usually seen when the chest is locally hit by a heavy object, or when the chest muscles are strained after moving heavy things. This is because the arm activity will involve the pectoralis major, pectoralis minor and other muscles of the thorax, thus causing local pain. 2, it may be thoracic costal arthritis or costal chondritis, both of which are local aseptic inflammation, and because the arm activity will also pull the muscles of the thorax, so it will cause local inflammatory pain, and even aggravate the original pain.