It used to be that sometimes when I would drink Coke, it would make it difficult or even painful when I pee. It hasn t happened for a while but I really never drink Coke anymore, only Root Beer or Dr Pepper. Today I m at Walgreen s and I couldn t say no to a cold bottle of vanilla Coke. Again, having trouble peeing and even painful. I know of all the sodas, Coke is the worst one, but what is causing this pain?