A single main point doesn’t have to be kept to a single paragraph, especially if you are writing a relatively long research paper. Main ideas can be spread out over as many paragraphs as you deem necessary.
If you are struggling to come up with a topic that feels “just right,” ask your professor or coworkers/classmates for advice. They will likely have great ideas that, even if they aren’t options for you to choose, can inspire you with new ideas. Asking a professor for help may seem frightening, but if they are worth anything as a professor, they want you to be successful with your work, and will do what they can to make that happen.
Although you may be limited by specific classroom or work related guidelines, choosing your topic is the first and most important step in your research paper project. Regardless of whether your topic can be anything you want or has rigid requirements, it is important to keep a few questions in mind: Is there enough research available on this topic? Is the topic new and unique enough that I can offer fresh opinions? Is it pertinent to my class/occupation?
Whenever possible, look for peer-reviewed empirical research. These are articles or books written by experts in your field of interest, whose work has been read and vouched for by other experts in the same field. These can be found in scientific journals or via an online search.