What can cause lumps in the head or behind the ear?

Many of them are called: Lipoma. which basically a collection of fat or Seboma which is an ingrowth of sweat gland. both are benign.

so dont worry about them.

i hsve a lump behind my ear, they said it was a bone growth . i wear glasses and they look crooked cause of it. there is nothing to do about it.

this could also be due to the dandruff in your head(ie if u have it).It could also result in slight fever sometimes.