There can be outgassing of chemicals from commerical places.

My husband now works at home, (for security reasons), but his job requires him to go to the office for meetings, and to turn in his cases, a couple times a month. He may go more often, or less depending on what is happening.

He says whenever he goes there he itches all over. Itchy and stinging. His building is new, and also shares facility with the entire computer network that is hubbed in our metro area for the gov't. I suspect he is getting exposed to either cleaning fumes, there, or outgassing from carpet and/or building materials. He has no PN symptoms or arthritis like I have, but he does get stiff now and then since he is over 60 now.

When you work in the garden with chemicals, some get inhaled even if you wear gloves.

I'd let up on the arm resistance work. You can do that walking outside with weights. If you stop the gym for a while, and feel better then that points to something there. Chemical or overuse from working out.

One has to be a detective these days. You can not expect or rely upon a doctor to find much with PN... there are just so many triggers! And the list is growing!