The human body has endogenous biological rhythms. One of those rhythms is the circadian rhythm, with a cycle of approximate 24 hours, that is responsible for regulating many important functions of human body. In this contribution, we propose a nonlinear coupled differential equation for modelling some agents responsible for the circadian rhythm under the influence of pain. We show results concerning the well-posedness of a solution as well as an analysis on the synchronization for each agents. We use a multi-agent simulation strategy of an corresponding model as an alternative interpretation of the pain influences in the behavior of the circadian rhythm
