Answer: While the clitoral hood usually does cover at least part of the clitoral glans, I am aware that in some cases it does not. The hood is just the continuation of the loose skin that covers the body or shaft of your clitoris. I am not aware that it is a problem, and since you can masturbate to orgasm it does not appear to be a problem for you.
Please verify that what you believe to be your clitoral glans is not actually your clitoris covered by an adherent or closed hood. You should be able to see where your inner lips attach to the bottom center of your clitoral glans. Your clitoral glans should be of a different tissue type than the surrounding tissue, and perhaps very sensitive to touch.
There is a very small chance your hood was removed when you were an infant or child.