Mine were mainly fatigue, brain fog, stiffness and pain. This was usually caused by polyester. For several years at my sickest I could be incapacitated for hours or days by wearing things with even a small percentage of p in them!
Rare;y, rashes and raw places on skin in contact. This was usually from residues in the fabric, perhaps detergents and such, not the fabric itself, and could be removed.
I am much better now, and can wear pretty much any fabric. Still have to be careful about some of the additives, though.
What are you doing to try to recover from your MCS?