The dull feeling under your ribs could be from irritation of the bile duct by the rapid and prolonged passage of stones and toxins.
This can be irritating, especially if it doesn't eventually stop. I've noticed that this twinge is especially noticable while seated and leaning forward, and while breathing deeply. Anything that increases internal pressure at this point (midpoint along the inner edge of the right rib cage) makes it more noticable.
I've had success with Liver Cleansing support herb complexes. The liver herbs also seem to strengthen the liver, helping it eject more stones the following month. Any complex should include milk thistle and dandelion. In addition, I also take lecithin and milk thistle when the pinching/throbbing feeling persists.