Shoulder height difference may be caused by heavy physical labor, old injury, scoliosis, cervical spondylosis and other factors. 1. Heavy physical labor: prolonged use of one shoulder to carry heavy loads may lead to muscle imbalance between the two shoulders, so that the muscle strength of the shoulder and neck area is uneven, which will lead to different shoulder heights, only that the difference is not particularly obvious. 2. Stale injury: one side of the shoulder has suffered acute injury, fracture, poor healing after fracture or deformity, it is easy to lead to the two sides of the shoulder is not the same height. 3. Scoliosis: it may be caused by prolonged poor sitting posture, poor bone development and other factors, which will lead to scoliosis, and the phenomenon of different shoulder heights will occur. 4. Cervical spondylosis: prolonged and excessive head bowing may induce cervical spondylosis, which causes compression of the nerves and spasm of the shoulder and neck muscles on the affected side, resulting in uneven shoulder heights, accompanied by symptoms such as radiating pain and numbness in the upper limbs. If the shoulders are not the same height and there are other abnormalities, it is recommended to go to the orthopedic department of the hospital for appropriate examination and treatment.