When looking at pain experienced at the neck, most medical practitioners tend to assume that the cause of the pain is from a structure in the neck like a herniated disc, stenosis, or degenerative joint disease. I have found that in most cases, the cause of pain at the neck is due to a muscle imbalance between the pecs, anterior deltoids and the biceps versus the muscles between the shoulder blades, the posterior deltoids and the triceps. Where this explanation might seem vague, it might make it clearer to you if you understand how a muscle imbalance can affect the length that a muscle is maintained and how that length affects the ability of the muscle to create force and achieve functional tasks.
In this case, the muscle imbalance described will cause the muscles in the front of the body including the chest, shoulder and upper arm to shorten. This creates a posture called forward head and shoulder posture. When this occurs, the shoulder blades move away from the spine. In doing so, the muscles that attach from the skull or the spine to the shoulder blades are lengthened. One of the key muscles in this region is the levator scapula. This muscle is responsible for supporting the head when in an upright position. If these muscles are lengthened due to an inappropriate position of the shoulder blades caused by a muscle imbalance, they lose their ability to create force and support the head. This makes the muscles work harder to perform the same functional task, which makes these them susceptible to straining or to spasms. This is what causes neck pain in most cases.
To explain a little further as to why lengthening of a muscle can alter its ability to create force and achieve a functional task, I would like to briefly discuss the anatomy of a muscle. A muscle is comprised of billions of fibers. Each fiber is comprised of two proteins, one is Myosin and the other is Actin. Myosin looks like billions of golf clubs lined up one after the other. Actin looks like billions of golf balls line up one after the other. When a muscle is at a proper length, the Actin and Myosin fibers are aligned. When a muscle is going to contract, the billions of golf clubs grab the billions of golf balls and pull themselves to the adjacent golf balls. It is a simple equation: the more golf clubs grabbing golf balls, the more force a muscle can create. Now look at a muscle that is severely shortened or lengthened. In these cases, the number of locations where golf clubs can grab golf balls has been severely diminished because of a misalignment of the clubs and balls. The Length-Tension Ration law says that a muscle creates its greatest force in its optimal length. If severely shortened or lengthened it loses it ability to create force.
Going back to the case of the levator scapulas which are responsible for supporting the head; if these muscles are excessively lengthened due to a muscle imbalance that alters the position of the shoulder blades, then there is less ability of these muscles to create force. They are still responsible for supporting the same weight of the head but with less force output,; the muscles are then destined to strain and create pain. This is why the only solution to resolving neck pain is to resolve the muscle imbalance between the pecs, anterior deltoid and biceps versus the muscles between the shoulder blades, posterior deltoids, and triceps.
Fixing that imbalance will create proper posture which maintains the shoulder blades in their position in relationship to the skull and spine. This keeps every muscle that attaches from the skull and spine to the shoulder blades at their optimal length allowing them to create their maximal force. The muscles will be able to perform their functional tasks with the least chance of straining, going into spasm, or creating neck pain. This line of thinking regarding muscle balance and proper length of muscle can be related to any joint in the body.
