Hello, I have what feels like a very hard, non-moving lump which feels like it is attached to the side of one of my thoracic vertebrae . I would estimate it to be about the size of a ping-pong ball, and is only able to be felt when lying down on my stomach . While it doesn t cause outright pain , it is very tender when massaged or direct pressure is applied to it. Do you have any idea what this could be? Thank you so much, Leslie