lumps under feet

I”ve been working 10 ton 14hour days for years and after a few I developped two lumpsplantar fibrosaunder my right footIn the plantar arch, which at times were very painful whether I walked, ran,stand, shifted my body weight or sat so much so that I had to have them removed surgicallyDuring the recovery period of total non- weight bearing and crutches the situation caused me to put a lot of extra weight bearing on my left foot which has sinced developed a similar condition .Plese how could I medically explain this?