I Have Had A Small Lump On My Xiphoid Process,

I have had a small lump on my Xiphoid process, I've had it a few years after a gall bladder surgery. It never bothered me even thought is was the size of a golf ball. Three weeks ago I thought I was having a heart attack! Chest pain, couldn't breathe, nauseous, pain in my arm and now that lump is the size of a baseball and I have nonstop heart attack like pain. I went to er. They did an EKG, cbc and every test know to man and they said everything is fine. I went to my primary the next day and he gave me steroids and said it should heal within 3 weeks to 3 months. I can't see where you have a lump almost as big as one of your breast and the pain if off the chart aside from arm pain and nausea! My primary told me to go to the er if it gets worse... I couldn't imagaine how worse it could get! What do I do! On top of that I also have a marble size know in direct line with the front and the pain goes from the front to the back.