This paper bases itself on a psychological perspective to make a theoretical and methodological proposal that shifts the concept of health towards the crossing point between biomedical and social sciences. To that end, it is suggested that the concept of Subjectivity should be placed at the centre of the discipline of psychology, understanding it from the theoretical perspective that intersects between post-structuralism, psycho-dynamic theory and gender. The objective of the article is to make this proposal through a case study about chronic pain without organic cause, an emerging, contemporary, controversial malaise that is becoming increasingly common, called Fibromyalgia in the biopsychomedical field, and which affects mainlybut not onlywomen. In order to pursue this goal, a new methodological instrument was developed: the psychosocial gender diagnostic, oriented toward capturing the dynamics of chronic pain. This methodology facilitates the integration of the connections between subjectivity, gender and health, while at the same time problematizes the excessive medicalization of modern day life.