It's all of the above. The central heater circulates air in a loop from floor to ceiling, more exposure to particles, dust, mold etc. The increased moisture you put into your room is beneficial to pathogen growth especially fungus. Rapid Temperature changes could trigger symptoms.
(Changes in) Environmental status will affect mast cells and it will affect you when they are too reactive, it won't bother healthy people. There could be something going on with sensory signaling as well (CBD can act on sensory neurons btw).
Since there is no doctor around that is competent enough to research mast cell behaviour in POIS you will be running in circles if this is the pathophysiology of your POIS and other symptoms.
Other than that, you should dump all this info into a dedicated thread of yours Vandemolen (lifestyle category). Put all of it next to eachother. The combination of symptoms doesn't make any sense unless you factor mast cells in IMHO.