Your doc is either not very experienced or he's putting on a good act/show (faking disbelief) because while it's true that for normal aches and pains, even the pain after a broken arm or leg, a dose like yours might be on the high side. HOWEVER, for anyone suffering from severe chronic back pain, your dose is nothing out of the ordinary, in fact.... many people require a lot stronger dose than that, and have for years, in order to manage their pain.

And why do you think tolerance has anything to do with it?? More likely the amount of pain being generated has increased and you therefor need a higher dose of pain meds to knock it down. In my experience, including lots of reading, etc. this tolerance thing is mostly another side of the opioid-phobia fear we have in this country! Even some recent studies showed that cancer patients who docs had thought were developing "tolerance" to the pain meds, thus requiring stronger doses, were in fact only responding to a worsening of their pain. (surprise, surprise!) Most painful conditions either get worse or they get better & go away. Back stuff like yours (and mine - 10 years so far) seem to get gradually worse, for a variety of reasons.) So my guess is that your pain has been increasing and it shouldn't come as any great shocker that your pain meds might have to be increased once in a while.

Here's the thing- until someone invents an accurate & reliable pain meter, docs aren't sure who's really in severe pain, who's just seeking meds, who's overreacting to a minor amount of pain, and who the stoics are who are underreporting their pain! It's a mess.
Forget about what people think, forget about what's a high dose vs a low dose (those can be seen as signs of drug seeking behavior) and instead simply and matter of factly report the facts- describe your pain (where, when, what makes it better, what makes it worse, etc.) and if nothing much helps, and tell the doc how the pain is affecting you - can you work, sleep? eat? walk, bend, or not?
The problem is we're all super uptight about *drugs* as in illegal drugs and pain meds- try to just think of it like it was heart medication or something like that- you tell the doc what's going on with you and he (hopefully) will prescribe the correct med and dose to manage it. (As an aside, with severe spinal pain, it is important to not always be chasing the pain- the main long-acting pain med should make the pain at least tolerable (like an annoying ache maybe) most of the time (and allow you some quality of life), and a second, shorter acting pain med should be available for breakthough pain or pain flare-ups (although many docs still are in the dark ages and don't understand this.) I recommend the book "The Truth about Chronic Pain" I wish all docs were required to read it!

Many of us who have had multiple spinal injuries, dislocations, surgeries, etc. etc. take a level of pain med daily that id way over what is listed as a lethal dose for a normal, (not in constant pain) person (and we're not only not dead, we're still battling pain half the time and no, we're not high either.) What's an appropriate dose of opioids for my level of pain is just that - it balances the amount of pain being generated, and without any drowsiness, or anything alse (constipation is the only thing you have to be careful about- otherwise opioids are very safe. ) All docs should know this, but many don't, which is inexcusable, in my opinion.
Trouble is, there are a lot of stupid people out thee who give meds away, who mix meds with other crap, who don't tell the doc when their pain goes away, and who end up dead, or someone else does, and every time it happens, it makes it harder for legitimate pain patients!

Unfortunately, most of us with severe chronic spinal pain had to go through several years of (varying degrees of undermedicated) HELL before we had seen enough docs, had enough films taken, demonstrated that we were not seeking drugs, etc. before we were finally prescribed an adequate amount and type of pain med to really control the pain. The the price you have to pay in our opioid-phobic society, sorry to say. And sometimes you have to find a good pain managment specialist before things get done right. Just be real open & forthright when looking for a new doctor - don't do anything that would look like "doctor shopping" or getting pain meds from more than one doc at a time- they really don't like that one! But that doesn't mean you can't look for and change doctors!

Dilauded works, but it can also be hard on your gut if you have a sensitive stomach. There are many good pain meds out there (and the pain patch for people who are opioid tolerant.) But asking for pain med by name can be seen as drug seeking- you should only care about having the pain go away, not which med you take.

Just me matter-of-fact about the pain and everything it does do you (how it effects you.) I'd keeps a daily pain log of pain levels, what you wee able to do, or not do, etc. If you have a spouse or respectable family member who can vouch for you, you might consider bringing them to your next visit, for moral support if nothing else.

And forget about "tolerance" (whatever that is, if it even really exists for people who take pain meds for real pain) and what a strong dose of pain med you're already taking (because your guilt or uneasiness is interfering with you're getting the proper medical care) and approach this whole thing very business like.
Say, "This is the problem, back pain of _____ type, that is worse when I do this, better when I do that, and keeps me from doing____ and _____, etc. . And you don't know whether the med isn't working anymore or whether the pain is worse, but the pain is not being managed properly. You don't expect to be completely pain-free all the time (ha! I bet you already figured that out on your own!) but this level of pain is too much because: ____________.

I felt really guilty about taking strong pain meds at first, too, and looking back I can see now that I was at least half the problem in terms of my not getting the care I really needed. It's weird how the idea of having to take strong pain meds can mess with your mind.

good luck & take care