Hi, I have multiple chemical sensitivities.
I was diagnosed by an environmental medicine specialist. For many years I took neutralization drops and that was very helpful.
Some time after getting my last mercury filling out, my MCS improved enough I quit taking the drops, although I still have issues.
As Jason was saying, it's caused by a fast phase 1 detox and a slow phase 2 detox. The fast phase 1 overwhelms the slow phase 2 and you get symptoms. So you can also try slowing down phase 1 and speeding up phase 2.
Lack of glutathione also factors in.
Vitamin C and milk thistle are helpful for me, but there are many other things to try. Niacinamide is one that Andy Cutler mentions (see the next paragraph). It's the amide form of niacin (as opposed to the nicotinic acid form, aka what is generally called niacin).
The root cause (at least for me) seems to be mercury + arsenic as mentioned by Andy Cutler. I'm following the Cutler chelation protocol, did metal testing and I have those two metals and also lead.
I have similar exposures to you with the paints. Whenever it is I can tolerate sauna, I will be doing that as well to get out the chemicals stored in the fat. If you have low adrenal function, and are losing a lot of electrolytes, and have trouble with summer heat and humidity - probably not a good idea to do sauna yet.