Sometimes My Left Eye Pupil Gets Larger Than The Right.

Sometimes my left eye pupil gets larger than the right. I notice it in the morning as I look in the mirror to get ready for the day. Sometimes my left eye does not see things as sharp as at other times. I notice this sometimes while driving. Also, at times I get a pain on the right side of my head always about 2 in. above my ear. I don't know if this are related.