I have suddenly developed a very sore lump on my left instep. I was having a pedicure yesterday and just about came out of the chair as the girl was massaging my foot. The lump feels soft and will move around, but is very painful when I press on it. I didn't feel it when I walk, but now that I know it's there... I have noticed a mild discomfort when I walk. I also have started a spin cycle class 3 weeks ago and am wondering if this is something that could be caused from the bicycle pedals? I've never had anything like this before.