Did they scan your gall bladder, though? I know pretty much nothing about exploratory surgery, but it looks to me like they 1) can't go up into the gall bladder itself to see if you have stones and 2) you can't tell it's malfunctioning just by looking at it with the naked eye (er... camera). Lower right side pain isn't typical, but pain can radiate and it can make you hurt along the right side or across your diaphram/ under your ribs, so that could be your problem. As Lil said, vomiting is not usual with IBS, but it is with gall bladder problems.
I think it, though, is also symptomatic of parasites and bad bacteria (such as h. pylori). Have you been checked for those yet?