thinking that all forces that influence us are chemical responses to stimuli is very simplistic and outdated. Human beings have cognitions, are able to reason, and able to take decissions. I think I spoke largely about morals before, lolWhere do those morals come from? We are not born with morals or ethics, we learn them or adopt them, mostly from out peers and society. You even changing your reality is simply a chemical response to stimuli.
Take it this way, you can experience nothing without chemical responses you cannot control.