I also have had problems with some harsh chemicals (especially industrial paint), and was diagnosed by a doctor with “multiple chemical sensitivity”, which is quite a controversial diagnosis. He says that sensitivity to chemicals is a central sensitization illness in which the central nervous system overreacts to stimulus that cause no problems to most people, causing pain and/or neurologic problems. He told me that the reason of this overreaction is a long period of stress that includes an intoxication or bad experience with chemicals. According to his team it is quite common for people who have chemical sensitivity to also have CFS or Fibromyalgia.
On the other hand, the psychiatrist told me that this problems with chemicals were further proof of me having a delusional disorder
It’s undeniable that this disease is extemely complicated to understand.