My left foot started giving me pain on underside of arch. Today the pain became more aggressive which I initially put down to being on my feet all day in work. The pain started to rTravel above my ankle like a swelling pain. When I got home I massaged the arch area of my left foot & it felt like I had a lump about inch wide deep below skin. No swelling obvious looking at it externally. It is very sore when you compress it. When I raise my foot following any short period of weight on it, it takes 5 mins to calm down to some degree. I checked my right foot too but no such lump apparent & no pain .