Why i feel fainting and dizzy and black vision when i lay and tilt my head backwards?

Dizzyness: If symptom of faintness and dizziness only occur with tilting your head back in a certain manner, it is quite possible the inner ear is involved, especially if the dizziness seems to be of a rotational/spinning quality. This should be formally evaluated- either by primary physician or a neurologist, since there are a few serious causes for this pattern which should be ruled out.