In a short story, the problem that moves the action of the story forward is known as the "conflict." Conflict refers to the struggle or issue that the characters must face and overcome during the course of the narrative. It creates tension, drives the plot, and keeps the reader engaged. There are several types of conflicts, such as internal conflict (a character's inner struggle), external conflict (a character's struggle against an external force or obstacle), and person vs. person conflict (a conflict between characters).
