Yes, our body does not tolerate some things very well but the indicators are never clear cut enough for us to realise unless we start actively cutting certain things out.
I had issues of feeling lethargic, brain fog, bloating etc. Through process of elimination I realised I had an intolerance to diary, cutting it out and replacing it with Almond Milk has been massive in improving my constant tiredness, random aches and brain fog.
Similarly, as mentioned above, if you read the ingredients of a loaf of bread or a pack or tortilla's, you'll be gobsmacked as to just how much crap they put in it.
A bread maker is the way forward - water, oil, bit of salt, flour, yeast - and that's it (of course, you can add seeds and other good stuff).
However there's a possibility you may just not react well to certain grains in which case you'd be better off avoiding bread or looking at alternatives.