Hello! I have what seems to be an enlarged lymph node in the back of my neck, where back, shoulder and neck meet. Not really big, I don't think it's bigger than 1 cm, 1.5 cm at most, but pretty hard. It pops out more when my back is tender. It's been there for almost a year, I went to my doctor when I found it and he said it was nothing, blood work was ok. But it's still there. Should I concern?