What is pain? Pain is an unpleasant sensory and emotional experience that occurs when the body is injured, and is the clinical manifestation of a complex set of pathological and physiological changes, which can be localized or reflected by systemic diseases. How does pain occur? Pain can be divided into headache, neck and shoulder pain, chest and abdominal pain, back and leg pain, etc., and from the source of pain, it can be divided into soft tissue pain, joint pain, neuralgia, etc. The causes of pain and pain itself are very complex. Classification of pain From the course of the disease, pain can be divided into acute pain and chronic pain, and from the part of the body, it can be divided into headache, neck and shoulder pain, chest and abdominal pain, low back and leg pain, etc. From the source of pain, it can be divided into soft tissue pain, arthralgia, neuralgia, etc. Acute pain is mainly divided into two categories: inflammatory pain and traumatic pain, and inflammatory pain is divided into infectious (such as appendicitis pain and hand and toe infection pain, etc.) and non-infectious (such as strain pain and gout, etc.); infectious pain must be treated with antibacterial agents, while non-infectious pain can be treated with painkillers, and generally acute pain is not suitable for local massage. The most common chronic pains are rheumatic and rheumatoid pain, headache, shoulder pain and lumbar pain; the causes are complex and sometimes unknown, and general pain medication can be used, but it is better to identify the cause and then prescribe the right medication, especially when the pain persists non-stop or gradually increases. Cancer pain and postoperative pain Pain and its treatment is a widespread medical problem, and cancer pain is one of the most prominent ones, and there is still a lot of work to be done worldwide to enhance the awareness and proactive treatment of cancer pain. According to the data, 80-90% of cancer pains are effectively controlled by the three-step treatment, but 10-20% of patients still cannot get satisfactory pain relief, which is an urgent and difficult medical and social task because the pain of these patients is so severe that it is difficult for specialists to control and patients and their families suffer for a long time. Currently, the following methods can be used: oral medications for pain relief; indwelling catheters with regular injections to relieve pain; transvenous indwelling catheters; and the use of nerve-destroying special drugs to achieve medium- and long-term pain relief. Post-surgical wound pain used to be considered inevitable pain, but now it is different. Transvenous (PCIA), trans-epidural injection (PCEA) pain relief can be used as needed, which can make the post-surgical period basically pain-free and promote post-surgical recovery. Intractable pain Intractable pain is most common in cases such as trigeminal neuralgia, herpes zoster pain and herniated disc pain, where the pain is so severe that it is unbearable for the patient, and in severe cases, the patient is restless, and ordinary painkillers are not effective.