I have a hard lump or something on my lower back. (not tail bone) Its about the width of my hand upward from my tailbone. I am so worried. I am reading all over and am scared its a tumor? ..I am freaking myself out. It is like the size of a large marble? It really seems like its my spine since its hard and whatnot but its much much bigger than the other vertebra ..feels like its on my spine, maybe a bit to the right of it ..I can't tell. ...and it is sore at times like when I sit . ..it feels pretty sore because it protrudes from my skin so far since I am pretty petite I mean I can feel my spine very well all the way until the very lower part where that bump is, so I can't tell if its directly on my spine or what. Please HELP! I am so worried and need to hear that its something other than a tumor or cancer. Please! Thank you for your time.