Haha, no way a doctor is going to buy that line of bullshit. This is not allergy medication we are talking about, its a schedule II controlled substance. If you told him that, then you are admitting to him that you are illegally consuming controlled medications and the person who is providing you with them is also illegally giving them to you. A doctor can't dime you out to police for such a trivial matter, but it isn't going to make him think very highly of you.
Also, watch out because you are getting dangerously close to APAP (acetaminophen) overdose, and your liver will be very angry at you for that. If you are thinking of taking any more than the 6 of those things (therefore going over 2000 mg of APAP) I would use a "Cold water extract" method to take most the APAP out and leave mostly just the oxycodone or hydrocodone. Google it if you need to know the process, there are hundreds of threads on how to do it and why it is important.
I'm just wondering......What is your definition of a "serious pain problem"? About how old are you (I am guessing you're young) and what causes your back pain (like do you just have pain in your back or is it secondary to an actual diagnosis)?
Do you actually get prescribed anything for pain? because you make it sound like you do, but you are not specific enough.
BTW, this thread is probably just going to be closed based on the fact that this site is not designed to help give you suggestions on how to score drugs for "recreational use" from your doctor. If it is indeed a true pain issue, then there is a mega thread dedicated to pain control. But your post is awfully confusing, first you say you take these things recreationally in doses that are obviously in the range of abuse (especially since I assume you have a relatively low tolerance. Then you start talking about back pain, so which is it. Because no doctor is going to prescribe you the amounts you are taking to get high and still have enough to steadily control a pain problem.