First of all, you need to see the prescribing doctor and tell him about your alcohol use. Tell him/her everything, your worries about withdrawing, but stress the importance that you also NEED this medication for the pain. There is a reason why these drugs are manufactured, because there are legitimate uses for them. There is nothing to be ashamed about for needing them, it is when you begin abusing them that the problem manifests. As long as you are honest with yourself (i.e., you really do need them for the pain) and your doctor, you are simply alleviating the suffering you would otherwise endure without them.
As for the alcohol, I think that Dknd4v is right, you can suffer severe alcohol withdrawl and even death if you quit abruptly. Your doctor may prescribe you a benzo, but be aware of this medication, as it too is highly addictive. My uncle takes benzo's (30mg) for alcoholism (he was a heavy, heavy drinker, much worse than you). He also uses a CPAP mask, but he is following the advice of his doctor to the T, because he is terrified of medication replacing his alcohol addiction. So far he is doing fine, which is why I know for certain you will be too, should you decide to seek professional help and advice. The important thing is to be open about your concerns to those close to you, including your doctor, so that you have a support system.
Good luck, and you will succeed!
may i ask why u want top come off the pain meds if ur still in pain? are u abusing them or is this the dose ur prescribed? how long have u been drinking like that? too detox off alcohol u have to be in patient because u can die from alcohol withdrawl if addicted