A common cause of swelling and pain in the middle of the lower back is supraspinous ligamentitis. The supraspinous ligament is a ligament between the spinous processes of two vertebrae, which is dense and less mobile. When long-term stooping work or sedentary, standing for a long time will lead to the supraspinous ligament continued tension, long-term past may produce strain. After strain, there will be repeated localized inflammatory exudation and adhesions, which will eventually cause aseptic inflammation, thus creating painful trigger points. When bending or sitting for a long period of time there will be swelling and pain, and on examination there will be more obvious pressure points. This type of pain is indicative of overwork or improper posture, and requires rest or adjustment of sitting posture and avoidance of prolonged standing.