Pain is an unpleasant sensation in human being that is caused by actual or perceived injury to body tissues and produces physical and emotional reactions. Presumably, pain sensation has evolved to protect our bodies from harm by causing us to perform certain actions and avoid others. Pain might be called a protector, a predictor, or simply a hassle. In this article, I will discuss some basic concepts of pain.

We all experience pain to greater or lesser degrees at various points of our lives. It is said that pain is the most common reason patients seek medical attention. But, each of us perceives a given pain stimulus in our own unique manner. The intensity of the response to a pain stimulus is largely subjective, meaning the severity of the pain can most accurately be defined by the person with the pain, rather than by other observers.

Our individual pain perception can vary at different times, even in response to the identical stimulus. For example, an athlete during competition may not be able to feel the tissue injury of a cut or a bruise until the competition has finished. We may feel more or less pain depending on our mood, sleep pattern, hunger, or activity.