Cracking your own neck or getting it to pop is quite a bit different than a good upper cervical adjustment. If you're getting a difference from turning your head one way or the other it's a pretty good bet your neck needs some work. Whether that will help your hearng or not, well, the only way to find out is get it done and see if it does.
The upper cervical spine has much more to do with the entire health of your body than just your hearing. If you're getting a change in your hearing by simply turning your head you better get it checked out for the health of the rest of your body.
I wouldn't want to see the hearing loss be the least of your problems.
Get it checked please. If you have to see another chiropractor.