Cutting only because addictive if you let it take over you, perhaps you're feeling you have no power over anything in your life so you just accept that as it is, you don't try to take control. Admitting this is the first step to getting help, solving what's causing this. Look back at your past and see what may have triggered you to do this. You need to tell someone who can actually help you and is trained in dealing with this, willpower isn't enough to get through this on your own, you shouldn't be going through this trying to hide what you call your shame.
The pain you think is being released is actually not being released, it's Endorphins that are being released into your body that make you think you are having a quick fix, but in reality you're just making things a lot worse, this isn't solving your problems and I guess you've realised this by now so just take a few days to think what your next step is. However, please, try and seek help because you're just harming your body and it won't thank you for it later on in life.
Message me if you would like to talk further or about anything else.