The trapezius muscle is a broad, flat muscle that extends from the cervical to thoracic region. It has three parts - descending, ascending, and middle. The trapezius contributes to shoulder and head movement. It originates on the occipital bone, cervical and thoracic vertebrae and inserts on the clavicle, acromion, and scapula. The trapezius elevates, depresses, rotates, and retracts the scapula. Stretching, massage, and applying pressure can help reduce pain in the trapezius muscle.