A research question is too narrow if you are unable to find enough information that addresses that question. It is possible that the question has been asked so few times that no quality findings have ever been reported on the question or the question has never been tested to begin with.
To broaden the question,
If you have developed a viable research question and are unable to find articles or other academic matieral that addresses that question, then it may be up to you to do the research yourself! Your research question will guide the research that is needed and conducted. You could be an important contributor who adds to the vast, and growing body of scientific knowledge.