Sympathetic nerve is a kind of autonomic nerve, which controls our heartbeat, blood pressure, whistling, heartbeat, etc. People with autonomic dysregulation, that is, people with high sympathetic nerve activity, resulting in tight nerves or tight tendons, if tight in the chest, it produces chest tightness, chest tightness pain, so that cardiovascular delivery is poor; if tight in the heart, it produces depression, anxiety, nervousness, anxiety, etc., and feel stressed at all times. Human tendon tightness or sympathetic nerve activity is too tight. Habitual tightness of the tendons of people, easy to make the sympathetic nerve tightness; conversely, sympathetic nerve activity of people, also easy to make the head, chest, heart tendons tightness, each other have an impact. The following diseases are also common causes of chest tightness: 1. Sympathetic chain syndrome Sympathetic chain syndrome is the pain relieved by blocking the sympathetic nerves that innervate the pain area with local anesthetics. Pain that does not respond to blocking sympathetic nerves is called non-sympathetic dependent pain (SIP). It is a clinical syndrome with multiple etiologies leading to long-term occult presence. Typical symptoms appear when ganglion damage is severe and compensatory capacity is weakened, and the diagnosis is often delayed, with major clinical symptoms such as pain sensory disturbance and vascular dysfunction. The disease can occur at any age, both sexes, and is not uncommon in clinical practice. 2, pediatric cervical sympathetic nerve palsy syndrome Pediatric cervical sympathetic nerve palsy syndrome is also known as pediatric Horner syndrome, pediatric Bernard-Horner syndrome, pediatric Claude-Bernard-Horner syndrome, pediatric cervical sympathetic nerve palsy syndrome, pediatric cervical sympathetic nervous system paralysis, etc.. The nomenclature of Horner’s syndrome is not entirely consistent because of the controversy over the author who first discovered the syndrome. 1869 Swiss Johann Friedrich Horner described the syndrome in detail and scientifically elucidated the mechanism of its occurrence due to sympathetic nerve injury in the neck, so the nomenclature of Horner’s syndrome is most widely used. The typical clinical features are slight sunken eyes on the affected side, narrow pupils, ptosis, and little sweating on the ipsilateral side.