There are two main reasons for the pain in the middle of the back when bending over: 1, due to strain or strain on the interspinous ligaments and supraspinous ligaments between the spinous processes of the back, such as excessive strain on the ligaments of the back when bending over and lifting heavy objects, which can lead to strain, bruising, swelling and inflammatory edema and pain, as well as long-term head-down and bending movements, which can also lead to strain on the supraspinous ligaments or interspinous ligaments. 2, due to the paravertebral muscles next to the spinous process, such as the erector spinae, rhomboid, rhomboid, and scapularis, these muscles have strains or strains. The situation, will form a sterile inflammatory lesion in the local. When bending over, the tissues in this location are stretched and pain is easily experienced.