Hello~I am sorry you are going through all this pain. In regards to the surgery, I feel you definitely should have it, the pain could very well be from those stones. I wouldn't worry about it until after the surgery and the pain returns (if indeed it does).
If you are truly concerned that it is a hernia, then I would get a second opinion, this might help settled your mind more, but as I said, from what you said was discovered on the CT scan of the gall bladder, it appears it does need to be removed.