What Causes Sudden Sharp Pains In The Head, Lasting For Seconds?

My wife has been having very sharp pain in her head which make her scream and seem to be getting more severe .she has been getting them for a year or more.they come suddenly and have last for seconds but have been increasing in length.they come at different times without warning.they seem to be behind her right ear.she also has pain in other places on her head at times.we had an auto accident last February and banged her head,was checked at hospital and had a cat scan done and told all was well.now we are waiting to hear from neurologist to be checked out.what do you think could be the cause of This?