Ever since I'm about 18 I have been on a slow worsening slow towards (physical) pain, dizziness, weakness, etc. For a long time what was happening was a complete mystery!
It's a little bit in a suicidal mood that I moved to Australia, far far away from France and all my friends!
Sadly (!) it was a failure!
First, when I came to Australia and ive at my sister for 3 months (she lives on the far north end of Sydney, in a piece of little populated and expensive jungle) I got better!
A first mildly helpful discovery that I was, somehow, sensitive to car pollution. And it was getting (very slowly) worse every year.
I tryied to find work in ever depopulated area. As a coumputer programmer this is hard! And it's hard to change job when you are weak and prone to cripling pain way too often.
Anyway, fast forward, in March 2009 I discovered about MCS, Martin Pall's paper on it. I started to take his tablet from ProHealth. Well, it slowly started to improve but it was so slow. And still prone to many setbacks.
Then I saw a local doctor who is "treating" MCS (read: make it a little bit better) and he discovered I also have Celiac disease! So, after some initial resistance, quickly crushed by the weight of evidence, I stopped eating gluten. I got even better. But still had some setbacks.
Then in November 2010 I realized I also had food intolerance (is this thing going to end?!). It's not too clear what I'm intolerant against. I have an incomplete short list which helps though..
And now, if I'm careful with what I eat and not unlucky for 3 weeks in a row, life is quite good! 
Working on making it last! On average I have a (small now) setback every 2 weeks... 
A relevant TED video about something close (identical?) to my problem :~