"These are the sons that David had while he lived at Hebron…." 1 Chronicles 3:1 (MSG)
I'm currently reading a trilogy of novels. The first book felt a bit scattered and I struggled with parts of it. Only now, as I get into the middle of the second book, are the pieces coming together. Many of the things that confused me in the beginning are making sense, and I'm gaining an appreciation for the larger story told by the author.
In a similar way, the Old Testament can feel incredibly boring and confusing until you start connecting the dots and see how the whole of the story fits together.
When reading the Old Testament books of history, it's important to remember that David is a key figure. Not only is he key in understanding the Old Testament, but he is a key figure in the story of Jesus and beyond. God promised David that his throne would be established forever. When the Kingdom of Israel split after Solomon, the southern kindgom (referred to thereafter as the Kingdom of Judah) remained loyal to the line of David. All of their kings were descendents of David. The northern kingdom (continuing to be called the Kingdom of Israel) became a free-for-all in which the throne went to the most powerful (or treacherous) person who could ascend to the throne.
Because of God's promise to David, the prophets knew that the Messiah would be born of David's line. The family trees of Jesus listed in Matthew and Luke (one is the line through his mother and the other is through his earthly father Joseph) were critical in establishing that Jesus was descended of David through both.
The more you understand of the larger story, the more interesting the individual stories and chapters become.