The intercostal muscles are found between the ribs. The muscles can contribute to pain in and around the rib cage. They are also a major contributor to pain in the sides and in between the ribs known as a side stitch.
The diaphragm is a muscle found under the lower ribs. It can contribute to breathing problems, pain in the chest, ribs, and can cause sharp pain in the side known as side stitches.
The sternocleidomastoid are the two big muscles located on each side of the front of the neck. These are the most 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.