Hey there,
I "officially" have fibromyalgia - along with joint hypermobility in a few joints and a bit of laxity in some others. To me getting an official diagnosis of fibro was no big deal; it is, to me, just a word, which makes me feel no better or worse than I did before. In fact, it may be of help to me to have a diagnosis. (I'm not trying to play down how you're feeling, mind you!)
Me, I've got some muscle knots and pain, joint clicking and some pain, tingling/burning sometimes, bad sleep quality, some TMJ issues, fatigue, a few sensitivities, etc. I'm quite sure that stress plays a role, too, and possibly genetics. I sure know that I've been stressed over some things the last several years!
The Rheumatologist I saw was a good guy; he said that he doesn't just want to send me "to a doctor who's going to drug me up with painkillers and narcotics". His first line of response always consists of alterations to diet, lifestyle and stress.
Anyhow, on the note of magnesium, I see you mentioned infusions. That sounds good. Can't say I've researched why some people may not hold onto magnesium in their systems, however. Though I do believe that it's a critical mineral for many functions and can probably be easily depleted during periods of chronic stress - so if you are stressing a lot, that could be (maybe) a part of it. I think it can also act as an adrenaline antagonist (someone correct me if I'm wrong about that).
Have you tried supplementing with Malic Acid? I've read that it compliments magnesium, and some people with fibromyalgia reported significant pain reduction with the two in conjunction. I think Malic Acid, or Malate, plays a critical role in the Krebs Cycle (lots of folks with fibro have a problem with energy).
Now, this may sound really far out to some people, but reading the forums and book reviews, I've seldom seen a therapy that has so many positive (not all, but certainly in the high majority from what I've noticed) reviews when it comes to fibromyalgia.
There's a doctor from the States who observed that some of his fibromyalgic patients who were taking cough syrup (don't laugh, I'm being serious, here) which contained a very safe expectorant called Guaifenesin had some symptomatic improvement. He concluded (I'm not sure if it was through clinical observation and speculation alone, or in vitro or vivo tests) that - and I'm probably paraphrasing this big time, but the information is out there:
Some people have a genetically based enzymatic deficiency which can lead to the buildup of phosphates in the cell's mitochondria and other parts of the body leading to widespread tissue irritation/pain and impaired energy and mental function. Somehow this expectorant, Guaifenesin, binds to certain receptor sites on the kidneys and either triggers the removal of phosphates which would be excreted normally by people without this deficiency, or actually sweeps them out of the body.
The kicker is that the action of the Guaifenesin can be easily negated by the presence of salicylates, which are produced by plants. Therefore, the protocol involves strict avoidance of all herbal medicines, extracts, essential oils, and body care products - and even wearing gloves when gardening - to prevent interference with the action of the "Guai", as some refer to it.
Me, I love a strong herb tea, or certain medicinal herbals (and I'm not talking about cannabis, I don't touch the stuff) - and the thought of going without any herbs for medicine is hard for me to take, so I've not tried this.
But - some people (read the reviews on Amazon) have basically said that the protocol in this doctor's book "saved [their] lives". Some may dismiss it as quackery or implausible; there have been a few for whom it may not have worked. Some say it's very hard to do because symptoms may worsen initially. But enough people have sworn by it to warrant an open consideration, in my opinion.
Anyhow, that's the gist of the protocol. Could have gotten some things wrong, so don't take my word for it! Here's the book (no affiliation):
http://www.amazon.com/What-Your-Doctor-About-Fibromyalgia/dp/0446694444/ref=sr_1_1?ie=UTF8&qid=1291298299&sr=8-1
What the hey, it could be worth a look. Best of luck to you!