Start simply. You may not know a lot about your topic, so it is okay to start by asking a few basic questions to launch the research process.
What is income inequality?
Why is income inequality such a controversial topic right now?
Do some background reading. Look up your topic in reference books, CQ Researcher, and Issues & Controversies. Getting some basic background information on your topic may help you answer some of those initial questions, as well as give you ideas on how to expand your list of questions.
Be bold! Don't be afraid to pose questions to which you have no idea of the answer. That is what the research process is all about...finding answers.
Consider your list a work in progress. As you begin to answer your questions expect your list to change. You may add new questions, expand existing questions, and discard questions. This refining process is a natural part of the research process.