Four clinical signs of chronic pain as an independent suffering were defined in 2,010 patients with painful syndromes of various sites, including those that occurred in association with organic diseases. They are as follows: (1) The chaotic nature of spatial pain parameters; (2) Infinite limits of its temporary parameters; (3) Mutual suppression of "foci" of pain; (4) Replacement of the monocausal dependence by polycausal. The formation of painful syndromes is explained from phylogenetic viewpoints.