I have a quarter sized lump on my tail bone and has been there for a couple month. MY docotor said it was a lymthnode but the antiboitics he said would get rid of it hasnt done anything and has only grown in size and when it swells it causes pain to shoot through my back and into my arms and legs and it sometimes causes head aches. When this happens its very difficult to do anything as to standing, sitting , or even laying down. Any ideas as to what it is?