Firstly, muscle strain and myofasciitis of the shoulder and back. Long-term bending and head-down activities, as well as sedentary and improper posture lead to muscle strain of the shoulder and back, and after repeated strain, local exudation and adhesions will occur, producing sterile inflammation, thus causing soreness and pain of the shoulder and back, or numbness of the local skin. Secondly, because of the compression of the dorsal scapular nerve, people who have been engaged in excessive shoulder activities for a long time, as well as those who often bend over, lower their heads and work at a desk, may experience the compression of the dorsal scapular nerve, which, in addition to the soreness and numbness of the shoulder and back, may also radiate to the proximal end of the upper arm, but generally will not exceed the elbow joint. Third, cervical spondylosis and cervical disc herniation are common, causing pain and swelling in the back of the shoulder, and may be combined with radiating pain in the upper arm, forearm, elbow, and even fingertips.