Kidney pain and SWF

So, I did my first SWF (Salt-Water-Flush) (correct ingredients, etc) but it didn not work. And now tonight, I just got really bad sharp pains in my lower right side back, which I am guessing is my kidney? I have never had kidney problems before, and have never even had any kind of kidney pain. IS this caused by the salt my kidneys are processing? If do, why did my body absorb it? And is this going to damage my kidneys? IS there anything else I can take instead of doing the SWF (Salt-Water-Flush) again? I heard that you can take "milk of magnesium"? Is this bad for the kidneys and if not, would this work similar to the SWF?

Thanks
Tracy