When the bed is too soft, the physiological bending of the waist will be significantly deformed, and the muscles and ligaments of the waist will be significantly stretched, which will produce sterile inflammation over time, thus causing the symptoms of waist pain. If the bed you sleep in is too hard, the cushioning capacity is very limited, which can also lead to lumbar pain symptoms. Secondly, pain in the lower back after waking up from sleep is also common in people who stay in one position for a long time, always lying on their side or always lying flat when sleeping, which can also lead to muscle and ligament strain over time and produce painful symptoms.