My daughter (9) has a bump on the right side of head behind her ear. it is solid but goes down sometimes. not painful are all. any idea?

Lymph node: There is a small lymph node directly behind the ear....Right over the bone there....They can all swell and go down...If it is not painful and it keeps changing then no worries. When it gets bigger see if she is having any issues in her scalp or on her face..It is normal and nothing to worry about, .

Lymph node: Most likely it is a lymph node. A lymph node normally will increase in size during an infection somewhere in the general area of the lymph node. For example, an enlarged lymph node behind the ear is frequently caused by an infection somewhere on the scalp (like ringworm) or by irritated or flaky skin (like seborrheic dermatitis or dandruff). If it gets painful, or red or grows, see doc.