So it feels like the friendship is sort of one-sided? Am I understanding right?

There's a lot of components to a friendship. My first thought is has your friend shared things in the past and then suddenly stopped? I'd probably be more concerned with a change like this than someone who has always been private.

I agree with Ariane that everyone is different. Some of us are just quicker to share things and others are more cautious.

One other thought is to try to imagine what your friend might be feeling. Is there some reason he/she wouldn't be comfortable sharing? Perhaps you need to give your friend a chance to speak? Not saying that you talk to much because that would be a huge assumption on my part but just throwing it out there for something to think about.