I have a white bump on the underside of my heel, slightly to the inside. It s painful, even when I have my foot up. It s not very big, as wide across as a pen cap. I had warts on my feet when I was a kid, but I don t remember them hurting as much as this does. Otherwise, I am healthy, not on any medication currently. Female 21 years, overweight . What is this lump? What should I do about it?