When you incorporate your research into your story, do it with a light touch. Keep your protagonist's or narrator's perspective at the front of your mind; don't harp on the things that they will find unremarkable or irrelevant.
Identify scenarios in which you're likely to need information, and then determine both what you'll look for and where you're inclined to look for it.
I suspect that your difficulties with motivation are really at the heart of this. The theory section of the paper is in many ways the place where you sell your work, explaining why it matters to your colleagues and is worth reading. If you're feeling unmotivated or down on yourself, you're going to have a much harder time with that.
When you're wrestling with yourself, it's very easy to wind up in a stalemate, also known as being blocked or stuck. You don't want to give up on the project, because it means a lot to you. But you don't want to proceed, because it's painful and difficult and also maybe because you're mad at yourself for setting yourself a painful difficult task. So you sit there and look at those ten pages and wonder what's wrong.