Muis

Seeing that you need a woman's advice, here goes. Firts of all if it doesn't want to change from the one chainring to the other, it is problem with the derailleur, not the chainring. It could be have been bent on the way home from the Argus or something. The best would be te try and reset your derailleur from scratch and see what happens. If it doesn't work, you will have to ride with only one chainring sunday. If you know how to do it, it is not difficuilt, but a little long to explain here. Get a decent book on do it yourself bikefixing, maybe it will help. Just my humble womanly opinion.

I have experienced it once. Went for an ECG, nothing wrong, the docter said it was from sitting bend down a lot on the bike that winds get trapped (He is cycling as well). He gave me pills for that and it stopped. I can't remember the name. I think see a docter just to be sure.