I have a small lump in my neck that is not on the other side, what is it?

Lump in Neck. If the lump is tender it may be a lymph node swollen from an infection in the mouth, throat, scalp or skin. It can also be an infected cyst. A painless lump or one that grows is potentiall more serious and any lump that is persistent or growing - painful or not should be checked by a qualified head & neck or ENT physician.
Neck lump. Depends on many factors. Best thing to do with any unexplained lump is to see your doctor for an examination to determine if this lump is a problem or not.