Corene-
Although I'm sorry you get nauseous when eating I have to admit I was relieved because I get that too. Foods that used to be my favorite are yukky and that sucks! My mother gets that "lung rush" too.
Fast beating heart...ditto

Do you ever get difficulty with swallowing or that lump in your throat feeling?

Yes, I do. I always carry a bottle of water with me to help swallowing and cannot eat without water throughout the meal. Did your Mom find out what the lung rush was? I find it scary. Take care.