I think this will help.
Kun(君【くん】?)is used by persons of senior status in addressing or referring to those of junior status, or by anyone when addressing or referring to male children or male teenagers. It can also be used by females when addressing a male that they are emotionally attached to or have known for a long period of time. Although kunis generally used for boys, that is not a hard rule. For example, in business settings, young female employees may also be addressed as kun by older males of senior status.
Chan(ちゃん?)is a diminutive suffix; it expresses that the speaker finds a person endearing. Thus, using chanwith a superior's name would be condescending and rude. In general, chanis used for babies, young children, and teenage girls. It may also be used towards cute animals, lovers, close friends, or any youthful woman.
Although traditionally honorifics are not applied to oneself, some young women adopt the childish affectation of referring to themselves in the third person using chan.
