Poor circulation and things shifting. Exercise, castor oil packs or some other kind of moist heat, massage, and manipulation of accupressure points (right foot, between big toe and next toe, about an inch up on the foot there's a Depression between the tendons. Press it.), all help. And of course gold coin grass and other herbs are great. :)

When major organs and connective tissues become weak and strained, they get brittle, less flexible. So stones moving about will irritate more than usual. I've yet to have liver pain that's centered on my liver, it usually transfers to my shoulders or manifests as really bad acid stomach. Massaging the liver usually does the trick.