I have a large sore and very painful nodule on the bottom of back ribs. It is growing every week and almost doubling in size very rapidly. I just found another one just below and seems to be attached to spine rather than rib cage. Not moveable. I do have severe arthritis. It is also causing my back to spasm with just a small amount of bending over and standing back straight. I do not have this on the left lower ribs. I really would like to know what this is because it very much has affected my ability to even perform ADL s. It is constant pain. Feels very hard, smooth, and rounded.