I have a large hard lump behind my ear and get frequent sharp headaches is this normal ?

Depends: Depends what you mean by "normal".....Aa lump behind the ear may be a lymph node that is enlarged...That is normal as it is doing its job. If it is infected it will be tender. It may or may not be related to a sharp headache. Your symptoms are best evaluated in a visit with your physician so you can be examined more details obtained. This is hard to answer without seeing you.