Forget the common phrase, "my back or neck is out" and focus on the reality of what is going on. The human body was designed for use. Any aspect of the body NOT used on a regular basis will soon undergo what is called disuse atrophy or disuse degeneration. It is a natural result of improper use or inadequate use of any given part. As with any changes the body undergoes, disuse degeneration occurs over time. It isn't something we can feel or notice outwardly such as pain. Only until the tissues involved reach "the limitations of matter" do symptoms usually present themselves. By then years have gone by.
Take this understanding and apply it to YOUR daily life. If asked, most of us could show a moderate range of motion--twisting, turning, bending. Ask yourself, "How often do I regularly use my spine in such a way?" "How often do I put my back and body through those FULL ranges of motion?" Not doing so will, over time, leads to injuries. A chiropractic adjustment places specific motion into a specific joint. Depending on the degree of immobility, and remembering that it can take years for such conditions to reach the symptomatic threshold, it will logically take some time and work to restore proper mechanics to the spine. Trying to decrease scar tissue buildup and stretch out what remains is not as simple as "putting a bone back in place." As the spine becomes more and more involved, affecting more and more joints, there can be spinal deviation as a whole unit. The forces of gravity, stress and the work we do all act to "shape" the weakened and mechanically dysfunctional spine.