Can a police car follow you in Colorado If so how far and if it happens to me a lot what can i do about it to make it stop?

A police officer has the right to be almost any place, and to do any lawful thing. Following you, particularly on public streets, is probably nothing you can stop unless you can show that there is some specific reason that they are targeting you. If you believe that there is some reason they would be specifically harassing you then I would suggest you contact a local attorney who would be in the best position to advise you.