The feeling of tiredness and discomfort in the back may be caused by the following reasons: 1. There may be local muscle spasm. If the patient sits or stands with the head down for a long time, it may cause muscle spasm in the neck and back of the shoulder, and then the patient may feel local pain, stiffness and unfavorable activities. In addition, there is a clear sense of fatigue. 2. There may be local fascial lesions, if the back of the shoulder is affected by cold or trauma, resulting in a sterile inflammation of the deep fascia. 3. There may be spine related pathologies, such as cervical spondylosis or thoracic subluxation, which can cause degenerative changes in the spine. 4. It may also be caused by overexertion, if the patient does extensive activities involving the trunk within a short period of time, such as lifting a large amount of heavy objects. If the patient does extensive activities involving the trunk in a short period of time, such as lifting a lot of heavy objects. When resting, the patient may feel abnormal due to muscle fatigue.