I don't drink any colas but I do indulge the tea some.THat is when they kill you when either passing through the ureter of getting stuck especially the jagged hard ones first time is always the worse. I get them chronically have couple in kidney now luckily no pain and won't have till the day they move then its on. Glad they caught it before you got into anything like that kidney backing up its called hyrdronephrosis and very dangerous as well as an actual kidney infection while not common is way more risky that bladder infection. I've learned real quick to stay away from things like tea and dark colas and to not let myself get dehydrated. Biggest problem I have is the lower protein diet I love my meats