@beachbum - I used to do a lot of bronze and silver brazing doing metal fab work on custom bicycle frames and in addition to some weird skin sensitivities I developed an allergy to certain fluxes; I used a half-mask respirator with P100 filters in the shop, otherwise even a whiff of certain chemical would give me "fluxhead"/"foundry flu" or whatever you want to call it. Basically a really miserable head cold/sneezing/etc that would hit almost exactly 24hrs after exposure and last for about a day and then clear up completely.
I got into pedal building (like a lot of people) at the start of the pandy, and very quickly noticed that I was having the same reaction to solder fumes as I would get from paste flux fumes etc. I spent $20 on benchtop solder fume extractor with a charcoal filter from amazon and it's basically cleared that reaction up completely. I don't have a dedicated space either and the portable fume extractor has been a real help. It might be the lead content but more than likely it's the rosin/flux that's triggering the reaction. You're basically snorting borax.