We’ve probably all written a relatively mundane scene. Suppose character A is having a conversation with character B (Traci, this might partially address your question about a character who has to tell back story). Suppose, also, that character A then has to go on to have a conversation with character C. Possibly, you could end up having two relatively boring character interactions back to back. In your revisions, one thing to try is to overlap these two scenes so that character A is talking to B and C at the same time.
Here’s a passage from Jonathan Safran Foer’s Everything Is Illuminated. In this scene, a Ukrainian tour guide, Alex, is having a conversation with his grandfather about trying to find a particular city. At the same time, Alex is also trying to talk with his American customer, Jonathan. On their own, either of these two conversation might not have had much life to them, but by combining them, a colorful scene is created, topped off by the Grandfather’s blind seeing-eye dog, Sammy Davis, Junior, Junior:
“How do we get there?” Granfather inquired me, who was in the front seat, because when I am in a car I always sit in the front seat, unless the car is a motorcycle, because I do not know how to operate a motorcycle, although I will very soon. The hero was in the back seat with Sammy Davis, Junior, Junior, and they were attending to their own affairs: the hero masticated the nails of his fingers, and the bitch masticated her tail. “I do not know,” I said. “Inquire the Jew,” he ordered, so I did. “I don’t know,” he said. “He does not know.” “What do you mean he does not know?” said Grandfather. “We are in the car. We are primed to go forth on our voyage. How can he not know?” His voice was now with volune, and it frightened Sammy Davis, Junior, Junior, making her bark. BARK. I asked the hero, “What do you mean you do not know?” “I told you everything I know. I thought one of you was supposed to be the trained and certified Heritage guide. I paid for a certified guide, you know.” Grandfather punched the car’s horn, and it made a sound. HONK. “Grandfather is certified!” I informed him, BARK, which was faithfully faithful, although he was certified to operate an automobile, not to find lost history. HONK. “Please!” I said at Grandfather. BARK. HONK. “Please! You are making this impossible!” HONK! BARK! “Shut up,” he said, “and shut the bitch up and shut the Jew up!” BARK. “Please!” HONK! “You’re sure he’s certified?” “Of course,” I said. HONK! “I would not deceive.” BARK! “Do something,” I told Grandfather. HONK! “Not that!” I said with volume. BARK! He commenced to drive the automobile that he was fully certified to drive.
As writers we may initially be scared to write such a scene, because we’re not sure that a reader will understand it. But, notice how our brains can deconvolve this mess and get all the information we need. Moreover, because the brain is constantly working throughout the passage, I think it becomes a more interesting read. Of course, there are multiple ways to revise a boring passage, but this is one way that might not come intuitively to us. And, it doesn’t only work with dialog. Action scenes and descriptions can also be shuffled together to give your writing new life.