In literature, a conflict is a struggle between two opposing forces. Often, these forces represent good and evil. Most of the time, the conflict takes place between the protagonist and the antagonist. However, a conflict can be internal (takes place inside the character's mind) or external (between the protagonist and a force outside of himself).
An example of a conflict is that of <em>Hamlet</em>. In this play, Hamlet has two conflicts. One takes place between Hamlet and Claudius (external), while the other one takes place between Hamlet and his indecisiveness (internal).