Lump on spine with symptoms. What could it be?

About a month or so ago, i noticed a golf ball sized lump on my back in the area of my left shoulder blade, but located in the spinal area. Now for a few months before this, I began having muscle weakness in arms and legs and stabbing pain throughout ribs and chest.cardiac workups showed nothing but rhuematiod titers came back with a positive result. Are they all connected? What does it all mean??