As I understand Post Modern and Post Structure, they are themes in thinking about Human Being that have concluded our being is of such a complexity that the center or structure once proposed will always be suspect. The confusion for the polysyllabic discourse -any thing with 'post' in front of it - is pretty much summarized by a lecture delivered by Jacques Lacan, a psychoanalyst, in Baltimore in 1966. It's title: "Of Structure as the Inmixing of an Otherness Prerequisite to Any Subject Whatever." Which might well sound more comprehensible in French.
Post Modern and Post Structure thinking is however very far from accepting my own notion of center which is somewhere in the very simple word 'random.' In another way, I have to think of life as having emerged from chaos and with the tools available to Human Being, we will only ever possess moments of insight, many of which will conflict because our brains are not big enough to hold it all. Nor do I call this position acceptance, or resignation, or without logic, or depressing, or wacky in any way.