Re: amitrip, it's really too soon to tell if it's going to be effective for you or not. The point of amitrip is that it doesn't actually knock you out, there are some mothers of infants who have posted here taking amitrip, and the answer given by Eloise, our lovely resident pharmacist (
) is that amitriptyline will allow you to wake up in the night if disturbed. So you will still be woken by pain, unfortunately 
The difference should be that it requires a little more pain, or that it's easier for you to drop off. By it's very nature, the response you get to amitriptyline on the first night isn't going to be the response you get to it when you're taking it regularly. It is probably worth continuing to take it for a couple of weeks to see if your sleep gets generally better. It is the sort of drug that gradually builds up in your system before it has an effect (or the best effect). I've been taking amitriptyline for a year now, and whilst it's helped my sleep almost from the beginning, I've only very recently noticed that it does seem to have some effect on my general pain levels.
Re: the "unresponsive" question... It is actually possible to have a genetic "fault" that means that you do not respond to opiates. These people tend to end up in A&E with their shoulders round their ankles, screaming in agony and getting no relief from morphine - because if it's more subtle than that no one notices you're completely unresponsive to it, it's just a matter of everyone being individuals.
I believe this is quite rare - I'm sure someone else can give you more info on it (I only know about it because I've seen it mentioned somewhere on the boards).
However... If you've had any help from your dihydrocodeine and oxycontin, at any point, this isn't you.
It is of course possible for people to become tolerant of the opiates once they've been on them for a while. This might be what's happening with you.
Absolutely all of this depends entirely on what's going on with you - these are just some general points or possibilities. You know how your body is responding to what you to do it, I obviously don't.
Re: naproxen, this is given out all the time for joint issues, but it gets very mixed reviews here from people with HMS/EDS. It's great for inflammation, which isn't a defining feature of HMS, so those people with inflammation may get help from it where others don't. Another question to ask yourself.
The obvious answer if you think your meds might not be doing anything for you is to come off them. BUT you should only make one change at a time (don't come off something whilst you're still adjusting to amitrip, eg.) and DEFINITELY only do it once you've discussed it at length with your health professionals and really understand what's going on.
Do you have a pain management doctor? If you don't, it'd definitely be worth a referral by your GP or rheumy as a pain doctor will have a much better idea of how to get all these drugs to work for you than other doctors.
Sorry for the massive ramble - just some things to ask yourself/think about. Definitely talk the whole thing over with your doctor.
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On the subject of amitriptyline, my GP has suggested I experiment with the dose to see if it's got anything to do with my hopeless fatigue. I sleep sensibly now I'm on it, and I do think it's helped my general pain level, so I'm a bit wary of taking less of it. Still - if I stop sleeping altogether I can just take it again! It'll be worth it to see if I can tweak my amitrip dosage and feel better.
) then I just skip the dose altogether, or take a reduced dose when I finally do get to bed.