The left side pain with heartburn is a sign of something other than Gallstones which is associated with the right side. You may have a hiatal hernia which is strangling your stomach. Also pain on the left side is sometimes to do with the spleen. You may like to google hiatal hernia to read more about this illusive condition.
Alternatively the herbs you were taking may have trigger IBS which is a very painful condition incurring abdominal pain that radiates out to the limbs depending upon which part of the bowel is affected. You can determine this my studying your stools for signs of chronic constipation.