One hundred and four patients who complained of chest pain or back pain in the region between scapular were studied. In most cases, anatomical location of pain was in the rhomboid or serratus anterior muscle. Hyperactivity of dorsal scapular nerve or long thoracic nerve which innervate those muscles was thought to be responsible for the pain. The hyperactivity of the nerves may be due to the spasm of the scalenus medius muscle which the nerves meet during their course to the rhomboid or serratus anterior muscles. Therefore, spasmolytic treatment including trigger point injection, physical therapy, laser therapy, or NSAIDs may be effective for the treatment of chest pain or back pain.