I had the same worry about kidney stones as my dad has had them (in his 50's and 60's) I am 34, and think I am too young for stones. It is comforting to know others have had the lower back pain as well...I thought I pulled it while swimmimng. I am really trying to not take any asprin during this time...I will try to increase water intake. Is the SWF (Salt-Water-Flush) still a good idea? Anything else?