Sharp Rib Pain: Anxiety or Something More?

Has anyone struggled with this particular kind of rib pain: it’s really sharp and debilitating, but it lasts for about five to ten seconds at a time. It comes in clusters, so it’ll happen about five times a day, all lasting less than ten seconds, but then won’t happen again for a month or so. It’s just my left side, and is extremely painful. The bursts seem to be getting longer, and I’m worried it’ll keep progressing. My doctor gave me an X-ray, which was clear, and thinks it’s a symptom of anxiety. Anyone have experience with this?