I've been sleeping in a stiff neck recently. What happened?

Always stiff neck, mostly because the patient's neck muscles are not sleeping well, or feel the tension spasm caused by the invasion of wind, cold and dampness, which leads to neck pain, limited activity and easy to get sick in winter and spring. The main reason for stiff neck is that the pillow is too high, too low or too hard during sleep, or it may be that the head and neck are excessively skewed, which makes the muscles on one or both sides of the neck stretch for a long time, leading to strength imbalance and local muscle injury. It may be because the fan is blowing, or the neck is cold or wet, so I don't pay attention to keeping warm. The muscles involved include sternocleidomastoid muscle, scalene anterior cervical muscle, long neck muscle, levator scapulae, trapezius muscle and so on. , and muscle spasm, resulting in radiation pain on one side of the neck. Some people think that it is due to lack of exercise, physical weakness, poor qi and blood, and neck muscle relaxation and contraction disorder. If attacked by external factors, it will lead to the obstruction of meridians, stagnation of qi and blood, and pain will lead to stiff neck.