Everything you described (points 2 and 3) is caused by histamine.
You are eating fibre which probably contains gluten. You need to cut out gluten and dairy completely as you are statistically highly likely to be allergic to them. After two weeks you will be "cleansed" of these and will start to notice more easily what other foods set you off.
If you can afford it get an ELISA allergy panel done by US Biotek (about 400 dollars) AND ALSO get a fructose malabsorption test (I paid 80 euros for mine).
If you are stuck on chicken and rice only, and seem to react to any new thing you try to add back in, then you may well be fructose malabsorbent. If you cannot afford a proper test, wait till your tummy is calm, then fast from midnight until 9am, then eat a whopping spoonful of honey and see what happens over the next 3 hours. If you get frantic gurgling and pain and later diarrhoea, you very likely have a fructose problem.
(If so contact me for a list of what to eat!)
Mould sounds very likely. I am having such bad problems with mould in my current house that I am seriously trying to convince my husband to move. I also find I can eat a lot more when I stay with my mother in England and always feel much better.
For me adding whole grain or fibre causes bowel congestion and / or terrible diarrhea and a painful distended stomach.
If I eat something that disagrees with me I find that charcoal is helpful.
Mould is also a problem for me but mould avoidance can be hard and not always possible when bedbound. I don't tend to be dramatically better when on holiday or when I left all my belongings for a trial. Better but no dramatically so. We are all different so trial and error sometimes.