There has been a big debate over free will for centuries among philosophers and psychologists. Sigmund Freud as a mentalist put the subject in this way: Heredity, environment, instinctive and social factors influence understanding of one's self.
I don't like to think we don't have free will in its genuine term but whether I like it or not I cannot pass by without pondering over some existing realities that challenges free will in its true terms. Our brain chemistry, our history and sex hormones have a strong effect on who we become. Any of these factors could be slightly different and then our present self would turn to some one totally different. We are like products of several prior elements and then at this point we decide to think and believe in this way, act that way and feel as we feel and we think we are free in our choices and I assume it's healthier to have this sense of freedom though.
I came to an article incredibly interesting from Nature Neuroscience titled: "Unconscious determinants of free decisions in the human brain". It was in fact the resource of my main talk in the presentation that I mentioned before. To put it short, in an experiment subjects were asked to press a button and 10 seconds before they become aware or conscious about their own decisions of which button to press, some certain regions in the brain showed activities indicating prediction and storage of the upcoming decision in those areas, this says there is this high-level network that begins to shape an upcoming decision long before the person enters awareness about that. This research is not obviously going to wrap up this old debate to any final conclusion but it's an open door for more questions in the field of hard core science rather than seeking for answers only through the philosophical theories.