You learn through trial and error what you can and can't eat. Dense foods like bread, crackers or cheeze for example are usually a big no no, especially first thing in the morning when the restriction seems to feel tighter. Your crackers just got stuck, you felt hot and sweaty (and more saliva too probably) because you body was warning you it was going to throw up. A horrible feeling I know, and the slime that came with it is normal, although it's probably better not to get yourself in that position in the first place.
Your chest hurts because of the strain and spasms your body has gone through, it will pass and you can only learn from your experience. I have no Fluid in my port and yet I can't eat many foods as I still have a tight restriction. Everyone's different so try and take it slowly and easy when eating now and you will get to know what you can and can't eat.
Good luck.