I experienced the same thing when I first started with the GCG. My advice is to reduce the dosage till you find a level that makes you feel good. You’re supposed to feel better from the GCG, not worse. If you get pain it’s a certain sign that you take too much.
Now, a year and over 20 flushes later, I have gradually been able to increase the dosage without feeling discomfort, but I still don’t take a full tablespoon as recommended. There have been periods when my liver was so overworked that I couldn’t take GCG at all.
Also be cautious with mixing GCG with other liver stimulating herbs, as it can be to strong for the liver. More is not necessarily better.