Your topic has to embrace the requirements of the assignment as well as what you are genuinely interested in. Instructors generally require academic topics, but you might not yet be comfortable determining what academic topics are. These resources should help you find a topic that is academic and relevant, and that inspires you. Also, please don't hesitate to talk with your instructor or your librarian to help you find the best topic for you.
Mindmapping is a good tool for brainstorming. Mindmup is free online mindmapping software. An added benefit to this tool is that you can share your mindmap with someone else and brainstorm together. Here's a tutorial on using mindmapping to start your research paper: