I've got a small lymph node just below/behind my left ear that is very hard and fixed. Its been there for at least 4 months now. It seems to move with my head when I move my head around. I'm pretty young and I feel otherwise fine. I went to a doctor about it who wasn't too concerned but ordered an ultrasound. On the ultrasound, its dimensions were 7x4x2mm and it had "benign characteristics". This is obviously good, but I know the gold standard is an FNAC. Is it possible that it is actually benign despite being so hard and fixed? Would you trust an ultrasound alone to tell you that its benign, or should I push for an FNAC?