A conflict can be rooted in the main plot, it can be rooted in a relationship between characters, or it can be both. Here are a few strategies for creating a new conflict in a scene.
.tension
Scene & Beat Types 201-02
Beats come in four types: action, reaction, setup, and deepening. A beat can only ever be one type. Most scenes are dominated by 1-2 types of beats, though they can easily include all 4.
Using Relationships 105-03
“No man is an island, whole unto itself.” People are always part of a network of relationships, a community. For most it’s a web of familiar faces, with individual relationships growing or fading, much like the tides of the ocean. Characters can even engage relationships without interacting with the other person, through memory and imagination. Similarly, some characters may personify an animal, object, or force of nature. A character struggling to endure a storm may come to regard that storm as a rival, with a will and personality of its own.
Intense Tension 104-05
Once in a while a scene needs something more, a touch of extra emphasis to increase the tension. Usually this means either asking a character to make a sacrifice, or forcing a character to endure and suffer.
Immediate Tension 104-04
Within a scene each character has a goal and obstacles preventing them from achieving that goal. This means every scene contains at least one conflict, if every character is collaborating or competing to achieve the same goal.