Rolling the bottom of your foot on a water bottle

I was having some arch pain in my right foot that wasn’t going away on its own, and my doctor gave me several different things to try, and this one is my favorite—take a frozen water bottle and roll your foot back and forth along the top of it for a couple of minutes. This pretty much took care of my particular problem, but I’ve continued doing it most days just because it feels great. (I find I prefer doing it standing up, but sitting down is fine too. Best done on carpet or a rug rather than a hardwood floor. A non-frozen aluminum bottle works fine too.)