What Causes Recurring Growth Of Corn On Toe Along With Severe Pain?

I have had a dermatologist and a podiatrist remove a growth from the side of my fourth left toe numerous times. It always returns with a vengence. Each time it recurs it is more painful radiating into the pad of my foot just like the picture shows here. I ve been told its a corn but how could a corn be that painful? This thing makes it hard to walk due to the pain, it feels like the pad of my foot has a piece of glass in it.. What can I do so that I can go for walks..This is ruining my life!