Is Weird Sensation In Lower Back A Cause For Concern?

I have been drinking 2 liters of water everyday because it felt as if in my backside a sensation was starting. Once I started drinking the water the sensation became unnoticeable. But now if I slack up on the water for more than a day or two I notice the sensation in my left backside. I thought it was kidney stones (previously at 20yoa I had gall stones). But nothing has ever come out and the sensation is not a severe pain but just a noticeable sensation. Urination okay, sometimes constipation but not enough to worry about from time to time. Should I be concerned, because I am 62 yoa and realized I cant eat like I used YYYY@YYYY