I’ve had this problem for years, but never really thought about it until now.
The problem is I have trouble reading. It’s not that I can’t read, I can do that rather well. But when it comes to reading books or articles, it can become a chore. The words start to lose any sense of meaning and I tend to not comprehend the reading. The other thing that can happen is that I lose focus on reading. Even if the book has my attention, I get antsy and can focus. So I end up reading for no more than a half hour. This happens on a spectrum; some books are easier to read than others. More modern books tend to be a little bit easier to consume, but the older the book and the more “thick” the book is, the harder it is to read. For example, when I was in seminary, you have to read a bunch of theologians. I was excited to be reading these books, but most of them were hard reads. Theologians like Barth and Tillich were a bit easier to read, but others like Friedrich Schleiermacher, were just impossible to read and comprehend.
I’ve been wondering if there is a link between being on the autism spectrum, which I am, and reading. I’ve tried to find anything online about reading and autism, but there is very little information. I did find this abstract from the National Institutes on Health that is somewhat helpful. I’ve wondered if I’m dyslexic, but I’m not sure. What I do know is that it can be frustrating to hear someone say they read something from the Federalist Papers and I want to read it, but I know that it will be nigh unto impossible for me to read.
What I would love is to find ways that would help me to read and comprehend. As hard as it is, I love to read. If anyone has any advice, I’d love to hear them.
The Clockwork Pastor 
My autistic daughter says this too. She mostly reads stuff online or manga, not books per se. If she does read books she reads slowly. It’s not comprehension — she’s very smart — but hard to keep the thread of the story, I think.