Hi there, for me it sounds like a potential allergy as you have said its sstarted up with introducing foods. I would do an elimination diet for yourself and for your LO, then at least if this continues you can rule this out.
I have to say I dont think its just a case of a "fussy baby" thats what Dr's say when they dont know what it is, in my opinion. also if there is an allergy or intolerance of some sort then it will flare up the reflux as well. Having an intolerance or an allergy can weaken teh immune system so an illness can follow this, anotehr reason to do an elimination diet as you certainly want to try and avoid your LO getting sick on top of that.
remember Im not a Dr though, just someone who has a refluxing, milk protein intolerance boy

and it does sound similar
