In the past three decades, a scientific revolution has occurred in the understanding of the experience of pain. However, a clinical revolution based on the new science is yet to occur. Pain is a multidimensional experience with many contributing and interacting biological/pathobiological mechanisms. These mechanisms may be nociceptive, peripheral neurogenic, central, affective/cognitive or relate to output systems such as the motor and autonomic nervous system. With a better understanding of pain-related neurobiology and some clinical decision making skills, reasoned attempts at a diagnosis of pain can be made. The essential question and first step related to clinical integration is to ask, "what is (are) the predominant mechanism(s) in a given patient's pain state?" This paper provides the underlying clinical biology of pain mechanisms and proposes pain patterns related to the mechanisms.