1.Is pain a symptom or a disease? People usually think that pain is only a symptom of the disease, and as long as the disease is cured, the pain will disappear, which is a misconception. To say that two patients with trigeminal neuralgia and postherpetic neuralgia, the primary disease has been cured and the patients’ various laboratory tests have been normalized, but the pain still exists and is recognized by the medical profession as the most painful, stubborn and difficult to treat kind of severe pain, which needs to be treated separately. The World Health Organization has clearly stated that acute pain is a symptom and chronic pain is a disease. Pain is usually divided into acute pain and chronic pain. Acute pain is pain that exists for a short period of time (less than three months), usually following an injurious stimulus, and is caused by the primary disease, and disappears as the primary disease is cured, such as a headache caused by high blood pressure, which is relieved once the blood pressure is normalized. Acute pain, on the other hand, may develop into chronic pain if it is not completely controlled in the initial stage. Chronic pain often persists after the primary disease has been cured and tends to get progressively worse, and can persist without any exact cause or tissue damage, when the pathological-physiological changes of the body are completely different from the primary disease, such as some patients with herpes zoster, although the herpes has disappeared, the pain still extends for several years or even for life. 2. Do you know how harmful pain is? Pain is an important signal that the human body is sick, it reminds people should go to the hospital in time to see the pain can make the patient mental pain, affect the diet and living, leading to a decline in the quality of life; serious pain will cause the body’s various systems dysfunction, immune deficiency and induce a variety of complications, and even lead to painful disability or affect the life of the patient. Pain usually shadows, which is the beneficial side of pain to the human body. However, in the vast majority of cases, pain can cause serious harm to the body and even lead to catastrophic consequences. Mild pain that affects a person’s sleep and mood is called the pain triad. People’s sleep is affected by pain, and poor rest can lead to anxiety and depression, which in turn can aggravate the pain and lead to sleep disorders, thus forming a vicious circle of damage to body functions and leading to imbalance of normal body functions. The World Health Organization has ranked pain as the fifth vital sign after respiration, pulse, blood pressure and body temperature. As one of the five vital signs, pain can effectively reflect the condition of human body functions.