Bad habits in daily life cause the malfunction of the brain, leading to tilt of the body, resulting in stiffness in the neck and shoulders.
If you keep the same posture for a long time, your brain misunderstands that the posture is correct posture and contracts the muscles to keep the posture.
For example, you always sit left side of your husband (wife) and talk to him (her) looking toward right side. Even if you look at the front, your brain thinks that looking at right side is correct posture, secrets dopamine, contracts the right shoulder muscle and your body tilts to the right side. To keep the posture looking at the right side, dopamine works hard, resulting in more tension in your neck and shoulders.
Always hanging a bag from one side of the shoulders also tilts your body. (Fig. 1)
In an experiment, a healthy person who doesn’t have the malfunction of the brain was asked to wipe a window with the right hand. There was tension in her right shoulder but no tension in her left shoulder. On the other hand, a person who tended to tilt her body to the right side was asked to do the same thing. There was tension in both shoulders including the left shoulder not used. This is the proof that she has the malfunction of the brain. (Fig. 2) (Fig. 3) Repeat of tiny habits in daily life causes the malfunction of the brain.