Despite continuous improvements in available pain treatments, many patients with chronic pain still remain insufficiently relieved. Although such therapeutic failures are often ascribed to pharmacological or psychological factors, difficulties in elucidating pain-generating mechanisms may be the main cause of insufficient pain management. These difficulties arise from several origins, including the unsuitability of the usual classification of pain, the exclusive use of etiology or symptom criteria as the main dimension of pain to guide the choice of therapeutic agents, the inadequate interpretation of sensory deficit, the lack of identification of the injured tissues, the absence of objective pain assessment by psychophysical methods. In this paper, we review briefly some fundamental knowledge to determine pain treatment based on the identification of the physiopathological mechanisms of pain. We advocate that once pain-generating mechanisms are known, it becomes possible to establish the appropriate treatment of pain.