A man is in conflict with three sides:
The struggle of man against man, which is when there are two people who have opposing ideas.
Man’s struggle against nature, which is when nature torments man through storms and other things. An example of that is "the old man and the sea".
The human versus self struggle is the struggle between good and evil and self-doubt within the human being, an example of that is the movie "The Village of William and Shakespeare"
And there is one of the other conflicts that was discovered recently, which is the human conflict versus man-made machines, and an example of that type of conflict is the Terminator series.