I've more or less been lurking on this thread. I find it interesting due to the fact I've used Bicarb for probably the past 20 years. I also use colgate on top of it. But I found over the past few months that my mouth burned slightly...so rather than giving up the Bicarb, I gave up the Colgate...and for me that worked.
I like the mild abrasive feature of using Bicarb..and because I drink lots of cokes or pepsi, I thought it would help to rid my teeth of any staining..they're actually quite white though..
Thinking of some of my children in Moldova..could it possibly be that you have the most mildest form of oral thrush? It's just a guess. We had this with a child a few months ago, where she had symptoms you mentioned.
I might tomorrow try switching the process and use the colgate rather than the bicarb and see what it does.
I do wish you well
Fr Bill