> I'm extremely curious about how you found out
Exclusion and desperation. I got nothing from various doctors despite problems that I thought should be treatable. It had very, very slowly gotten worse over two to three decades. It is very, very subtle, and until a threshold was reached I described myself as "100% healthy" - completely ignoring a myriad of increasing little problems. Because each and every one of them has alternative explanations, usually: aging, office/computer work, stress, wrong food, "everybody has problems", etc. Soooo much went away under chelation treatment that I didn't even have on the radar, things that I had attributed to the mentioned untreatable problems, mostly aging or stress or food. But it wasn't!
I thought that my problems seemed very treatable/diagnosable, but nobody even tried. "You take Nexium (a PPI) for the rest of your life" said a professor of gastroenterology, which to me was pure torture, I never felt as bad in my life as when I used that stuff. Then I found that I had a massive Candida problem, which had started when I took the PPI. A doctor confirmed it (the professor had ignored everything I had told him and thought it's all in my head), I was even given systemic anti-fungals (fluconazole), with huge positive effect, but then my hands where yellow... I then learned that Candida never is a root cause, always a symptom. Apparently I didn't have any of the usual medical textbook problems that lead to such a problem. The only thing left was something I found in the forums of the "crazy people": They claimed Candida often is a problem of people with a heavy metal problem. With nothing left to try and to lose I went down that route: Take measurements, find a specialist (I had to go very far), start chelation and see if it helps. Well, the measurements should middlish amounts of mercury, "You are in a gray zone but I can justify chelation therapy" said the doctor. The real proof came with the unexpectedly large success over the years.
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If I was a doctor I would not treat this condition. It is next to impossible to detect - basically, there is no known method to conclusively test if heavy metals are a problem or not. You can get indications, but only acute poisonings with large doses can be shown through a simple test. So how did we know in my case? I was "lucky" enough to have had a few special conditions that lead to an acute surge, so I actually had significant levels (of mercury) in blood, hair and urine. Most people with chronic poisoning won't have that though. The rest of the proof that that indeed was the problem was all the things that started to improve after starting chelation - many of them completely unexpectedly. For example, during chelation, after each round, the tissue around my right-side thyroid was "working" (very active, some pain). The result, shown a year afterwards: A 5 mm nodule in the twice-normal-size thyroid had completely(!) disappeared, and the thyroid was almost normal size. I had had endocrinologists show that nodule and the double-sized right thyroid unchanged over almost three decades. The endocrinologist examined me with ultrasound TWICE because he did not believe his results. There is a lot more, that was just one of the highlights because people like undeniable biomedical imaging proofs, so much better than me saying "I can sleep much better".
So anyway, as I was saying, if I was a doctor I would not treat this condition. The problem is that you need crazy people like me. This requires a long-term commitment for an uncertain outcome. You also need resources - money, TIME (you cannot go on living a regular employee life, the chelators only help get things started, your body has to do most of it, and it requires lots of time and you need to rest or it (the body) won't do anything). Most people would never have that patience, as a doctor you will make your life much harder if you offer those treatments. Not to mention that there is the potential to be right - and make things a lot worse: If somebody indeed has a heavy metal problem chelation may make it worse (it mobilizes more than it can bind, since no chemical bond is eternal and perfect), and if their body already is on edge...
Also, the whole subject is itself poisoned. On the one hand you have few options to show anything conclusively, no good tests, on the other hand the whole topic of heavy metal poisoning, or just poisoning, is extremely popular in "alternative health" circles. So even if you are a doctor, you really, really don't want to be seen working in this area by your colleagues. It's much more acceptable (by both your medical colleagues as well as insurers!) to offer homeopathy, as an MD, than offering chelation. At least that's my observation.
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> Do you think that people with your condition are misdiagnosed on a large scale?
I have no opinion about other people. A lot of things are very special in my own case. I certainly think the problem could be much larger than people think. On the NIH website I found a document that stated that mercury is far more toxic than lead. I took a course from Tufts University [0] about water treatment. Of the four weeks they spent one entire week, 25% of the whole course, only talking about lead. There were two professors, one for the engineering side, one for the medical side, and the medical professor cited study after study and showed graphs that the state of medical science is that the only safe level is zero (technically not feasible - thus not possible to have as an official limit). So there is a lot of attention on lead, has been for decades. I don't see nearly as much on mercury, supposedly much worse, despite there being quite a bit of mercury around us. For example, are you sure eating all that tuna and other sea fish, especially the predatory ones, is such a good idea? In my experience, the one I gained the last few years, involuntarily, the signs are extremely(!) subtle. You don't get "sick" or a fever. You may have a little bit of trouble with your eyes. Or you get problems with your carpal tunnel (RSI). The easy explanation will be, in both cases, that you spend too much time in front of computers. Or you have a bit more trouble finding good sleep. Your digestion acts up - but just a bit, if you went to a gastroenterologist they'd send you home "we found nothing wrong". The list goes on and on.
Are people misdiagnosed?
Maybe, I'd say probably - but there is no proven alternative. None. We just don't know.
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There is a general mismatch problem with medical knowledge based on observation and statistics: It is one thing to know that x percent of a certain population have a problem. It is a completely different problem going the other way: If you have an individual, in front of you, does (s)he have the problem or not? The probability you have is of no use to you, you have to make a decision, yea/nay?
A prudent doctor, knowing that the odds are low, will always say "no" in such a case, and statistically speaking that's the winning strategy from a public health point of view. You know you lose a few, but that's the minimum, if you tried finding out who actually has the problem (that you cannot reliably diagnose on an individual level) your overall statistics would get worse. That means knowledge of a problem on the scale of the population is almost useless when it comes to making individual treatment decisions. You need something on that (individual) level. In the case of long-term exposure (or any exposure) to low-dose poisons we don't have much that we can use, not on the individual level.
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[0] https://www.edx.org/course/biology-water-health-fundamentals...