What Causes Small Painful Lump On Back?

I am trying to find answers to helping me understand my most recent mri and X-ray reports that I have had on my back recently. I am seeing a back doctor in 2weeks but I am 41 years old and it is the worst it has been in 25 years. Also when this started about 2 months ago the small lump I have always had swelled up 2-3 in height also the same in diameter that is all new