I hope I'm not hijacking your thread, but this inspired me to write a letter to my past self, using the same skeleton as your post, regarding chronic pain.

Medical

Doctors will be of little help. The sooner you can stop viewing this as the fault of their own incompetence, the better off you'll be, both mentally and physically. Medical science can't effectively treat or even reliably diagnose a broad range of chronic illnesses. You will have to be the one who figures all of this out, so get started. It doesn't take that long to Google your way to a cutting-edge understanding of your condition, whatever it happens to be. And since it's a chronic condition, it's not like you're short on time.

That said, you should treat doctors as "consultants" to help narrow down and guide your own diagnostic process. Your depth of knowledge about your disease may come to exceed a non-specialist doctor's knowledge, but the breadth of their knowledge will always exceed yours. Use them as resources. Never stop seeing doctors, and never stop looking into new treatments, just be sure to remember that you are responsible for your own treatment.

If your condition could be treated effectively and completely, it wouldn't be chronic pain, would it? But whatever it is that you have, there will be treatments, supplements, therapies, drugs. Some of the interventions will be preventative, to avoid flareups or attacks. Some will be abortive or palliative, to chemically interfere when you are having an especially rough time. Always, there will be side effects, and much mental energy will be spent weighing the pain you're feeling with the side effects that you'll be bringing upon yourself. Develop and stick to simple decision procedures regarding where and when to take medications with severe side effects that you can employ even while suffering.

Don't ignore cliches or simple stupid things that work. Don't roll your eyes at weird hippie diets if you could just try them and see. Anything that makes you healthier and more robust, regardless of whether it directly effects the pain, makes you healthier and more robust and is therefor worth pursuing on its own merits and because it solidifies the base that you're operating on.

Social

Most chronic pain is invisible. Your dearest loved ones will lose patience with your condition. You will be short-tempered and exhausted often, and they will not understand that this is because you're in constant pain, and you'll get tired of using the pain as an excuse for your behavior, and they'll get tired of hearing your excuses, and you won't even be able to blame them. So don't blame them. Apologize when you are a jerk. Work on being less of a jerk. Work on not caring if the people around you appreciate how much you're suffering. In time, you'll develop a good enough mask that they won't even know anything is wrong. This will actually lower your level of suffering. The pity of others does not, in fact, help with your pain in any way, so train yourself to stop seeking it.

Simultaneously, you'll gain a lot of sympathy for the assholes in your life, as you realize that everybody is carrying some type of pain. When you apply your inner model of yourself as "decent person + chronic pain = asshole" to other people, you'll start inferring a lot more pain (psychic and physical) underlies human interaction than you previously guessed. You will internalize the lessons of the Fundamental Attribution Error in an instinctive way and blame people less in general.

Skill and Spiritual

Your attitude about your pain determines your level of suffering. Therefor, most therapy that intervenes on this level is effective for improving your wellbeing. You can even reach a level where you view your condition as a gift that drives you to keep becoming healthier and more in-control of yourself.

Pursue anything that trains you to accept your condition and to stop thinking of it as "unfair" while approximating a positive attitude. Anything that minimizes the odds of pain turning into actual depression is good, because depression plus chronic pain is not a pit that you want to enter.

Meditation is useful for attenuating suffering. It's not that meditation will give you a superhuman ability to shut off pain sensations. (Stop wasting time trying to use meditation to shut off pain sensations.) It's more that all the sub/semi-conscious chatter that constitutes actual suffering gets quieted down and then by themselves pain sensations aren't so bad. We make our own hell.

Thinking about serving other people is a great way to get out of your head and distract whatever mental module it is that gets into a foment about your own suffering.

I think this is a great area to explore, and probably one of the areas a rationalist perspective can most help teenagers.

I know as a late teenager, and in my early 20s, my sadness, depression, and anxiety, were part of my identity. It was how I dressed, how I thought of myself, the music I listened to, drugs I took. To take a quote from classic t.v. show 'Bojack Horsemen' I fetishized my own sadness. Breakups felt like a beautiful soul-crushing torture.

As I studied more science, read more, and took more interest in the scientific world, I started viewing my interactions with my own emotions in a more evolutionary and scientific view. I was less interested in my 'artistic sadness' and saw it more as a sort of depressing failure of my brain and evolution -- one which I could try to hack by exercise and eating well.

I wish someone had explained to me that as a man there were special hacks I could use, like lifting weights, testosterone, boxing, fighting, and other activities that I'm programmed to find rewarding. Particularly as a guy who was nerdier growing up, I never realized that passing on sports wasn't just a personal choice, but could seriously hurt my own personal development and confidence.