4months-shaking head

My baby girl is 4 months old....and at night and durning the day she shakes her head......i took her to the doctor cuz someone say it could be ear infection....but she dont have one.......and it worries me.......like this morning I had her sleeping on my bed and she was doing it in her sleep...and kinda crying out...........anyone know what is going on???

Aidan used to do the same thing... he never cried out but right when he woke up he would be a little shakey... I just chalked it up to half awake?? he kinda grew out of it and hasn't done it in a while...

I know my cousins little boy had an ear infection when the doctor said he didnt one time