PhilosophicalCat
Congratulations on your first flush, princessjade! It's the scariest one, since, no matter how much you might have read up on it, you really don't know how your body is going to handle it. Now you know!
Telman's response sounds right.
Another point to consider: With all sorts of matter suddenly being ejected through the bilary tubes, including semi-hard stones, the tubes themselves are likely to be irritated. Imagine rubbing something against your wrist, hard and fast. It will get red. If you keep doing that for 20 minutes (the length of time it takes for the initial release of stones, toxins and other materials) it will get red and inflamed. I would imagine something like that is happening throughout the bilary tubes in the liver.
What can you do about it? I've found two things which work well to help the liver heal. A liver cleanse complex (with a large collection of liver-friendly herbs) and milk thistle (usually one of the herbs included in the complex). I take the cleanse complex as recommended on the bottle, and take milk thistle in addition to that when I feel twinging in the main bile duct area. While I don't actually feel pain, I do feel twinges and a sensation like a knitting needle jammed where it has no rightful business being - under the right forward edge of my rib cage. These supplements have been very helpful in reducing and eliminating the twinges.
Good luck on your next flush!