I am a fifteen year old boy. I have had a very small lump (about pea-size or smaller) on the right side of my neck, around half-way between my collarbone and my ear. It is painless unless i squeeze it fairly hard, and if i poke it it moves, but always goes back to the same place. Do you think that this is serious? I weigh 55 kilos, measure around 172cm, and have had no medical conditions in the past apart from eczema ( i have also had chicken pox)