The sternocleiodmastoid are the two big muscles located on each side of the front of neck. These are most affected affected muscles when whiplash of the head / neck occurs. The muscles can contribute to pain throughout the head and neck area and can contribute to symptoms of vertigo.
The scalene muscles consist of three muscles, the scalenus anterior, scalenus, medius, and scalenus posterior. These muscles are prime contributors of thoracic outlet syndrome, and contributes to pain in the upper back, shoulder, chest, arm and hand.