Somatoform pain is a highly prevalent, debilitating condition and a tremendous public health problem. Effective treatments for somatoform pain are urgently needed. The etiology of this condition is, however, still unknown. On the basis of a review of recent basic and clinical research, we propose one potential mechanism of symptom formation in somatoform pain and a developmental theory of its pathogenesis. Emerging evidence from animal and human studies in developmental neurobiology, cognitive-affective neuroscience, psychoneuroimmunology, genetics, and epigenetics, as well as that from clinical and treatment studies on somatoform pain, points to the existence of a shared neural system that underlies physical and social pain. Research findings also show that nonoptimal early experiences interact with genetic predispositions to influence the development of this shared system and the ability to regulate it effectively. Interpersonal affect regulation between infant and caregiver is crucial for the optimal development of these brain circuits. The aberrant development of this shared neural system during infancy, childhood, and adolescence may therefore ultimately lead to an increased sensitivity to physical and social pain and to problems with their regulation in adulthood. The authors critically review translational research findings that support this theory and discuss its clinical and research implications. Specifically, the proposed theory and research review suggest that psychotherapeutic and/or pharmacological interventions that foster the development of affect regulation capacities in an interpersonal context will also serve to more effectively modulate aberrantly activated neural pain circuits and thus be of particular benefit for the treatment of somatoform pain.