question: I get a dizzy sensation when I lie down from a sitting position and the reverse, lying down to sitting up.  also get dizzy when I tilt my head backwards- as when I put eyedrops in my right eye.  What would cause this dizziness.  I was in Hawaii in May 2013 (extremely hot - no air contitioning) and the dizziness started then.  Can you explain what would cause this problem?