Struggling with the idea of research....

I feel like I need to have a big range of research and topics to write about in my paper. The more I narrow it down, the more scared I am that I won't be able to fill up 10 pages. How is this supposed to work? I always run into the problem that my papers are too short, and if they are long enough I always seem to repeat myself just to fill in space. This is my biggest issue right now and is stopping me from narrowing down my research proposal into something I can actually work with. I feel stuck.