Chronic pain due to a specific medical condition or injury can provide the basis for a social security disability benefits approval. Chronic pain is distinguished from acute pain where it is easier to understand the intensity and duration of the pain based upon the extent of the physical injury. The so-called ‘specificity theory’ of pain recognizes what we know from common sense that, for example, pain from a finger prick is less intense and long-lasting than that resulting from a toe amputation.
Social security law requires that pain symptoms be the result of a “medically determinable impairment that could reasonably be expected to produce your symptoms”. This is, I think, a codification of the ‘specificity theory’: excruciating and long-lasting pain can hardly be “reasonable expected” from a finger prick.