How come i get cold shivers during a viral infection like bronchitis or flu?

Part of the process: It has to do with the body's immune response to a foreign body, in this case, it is to the virus which attacks various cells. As the body tries to fight that off, various other reactions may occur like fever and chills. Btw-the actual flu is not all that common and usually when one thinks they have it, aka infuenza, it is really something else or a different but more common viral infection.