I think this is more of a personal question than a question that has a general answer. I will explain to you what the question is asking, and hopefully you can come up with an answer. :)
The question wants to know why you personally tell stories. Some examples include, because you want to share your experience, because you want to make people laugh/cry/smile/gasp (depending on the story), because you want to vent, because it makes YOU happy, because it is your passion, because you can express yourself, etc. Hope this helped! Share your final answer with me and I can review it for you! :)