The symptoms of back feeling very tired and uncomfortable may be caused by cold back, back fasciitis, thoracic spine small joint disorder. 1. Cold back: If the back is in a cold environment for a long time, it will lead to vasoconstriction of the blood vessels in the back, blood flow is reduced, and the muscles in order to maintain the temperature in the body, local muscle contraction will occur, and long-term muscle contraction will cause muscle spasms, resulting in the back is very tired and uncomfortable. 2. Fasciitis of the back: long-term weight-bearing exercise on the back can lead to strain on the soft tissues of the back, so that the local fascia damage, edema, degeneration and other inflammatory changes, resulting in back fatigue uncomfortable situation. 3. Thoracic spine small joint disorders: long-term stooping activities or incorrect posture will lead to the small joints of the thoracic spine dislocation, which will increase the friction with the surrounding soft tissues, thus causing back fatigue uncomfortable symptoms. There are many reasons for this symptom, in order to relieve the back fatigue and discomfort as soon as possible, it is recommended to go to the hospital for a comprehensive examination in order to identify the cause of the disease and actively carry out treatment.