I have a painless swollen lymph node in my neck for over two months. It does not seem to be getting bigger or smaller. It doesn't feel soft nor does it feel rock hard but it does move side to side when pressed. What could cause this. Had blood test come back good except bilirubin was 1.5. Mono test came back negative. Had blood work done to test for infection and none was present. Doctor said if mono test came back negative I should have nothing to worry about. I am 23 and really concerned that it may be because of some type of cancer and would like to know what else could cause it thanks