So i have had a cough/ cold past few days and i noticed i had a bumb come up behind my ear it is small, moveable, and painless is it a lymph node?

It could be...: There is an extensive network of lymph nodes in the head and neck region. When you get a cold/upper respiratory infection, it is not uncommon for one or more to become a little more prominent. Keep tabs on it. They resolve over time. If it becomes rapidly larger, red, inflammed and tender, get it checked out. Otherwise, take care of your cold!