Pain is an important manifestation of many diseases and may occasionally occur independent of the disease. Although many clinicians encounter the clinical symptom of pain on a daily basis in routine practice, the pathophysiology of various chronic pain conditions remains unclear; therefore, a standardized therapeutic approach is unavailable, and optimal pain management is challenging. Accurate understanding of pain represents the primary measure in pain alleviation, and much knowledge has been accumulated through basic and clinical research over time. We will continue research to gain deeper insight into the mechanisms underlying pain and aim to achieve "relief from pain," which constitutes the roots of medical care.