Baby with small lump on neck

My daughter has had a small lump in her neck since she was born, 12 mths ago. It is about the size of a pinto bean, movable, and somewhat soft. It is one inch below her hair line (behind her left ear) .  It has grown, but it is more like it is growing with her.  It is the same size proportionately from when she was born.  I have seen a pediatrician, Family practitioner, and a pediatric surgeon.  So far everyone says that it is probably a lymph node and nothing to worry about.  The pediatric surgeon did comment that it was strange to see an enlarged lymph node at birth and also strange that it is increasing in size .  THAT MAKES ME WORRY. Question: what would cause this lymph node to be enlarged (is there something else wrong)? Who do I go see about this?  ...how about a ear nose and throat Dr.?