I think you should go see a doctor. Even with PN I have never heard of any food that causes fainting after eating. I'm concerned about your feeling of pressure around your heart. I assuming you saw a doctor who diagnosed your PN, give he/she a call and let them know what's happening. I don't know if your continuing to drink but it causes many deficiencies in the body well as issues with some organs. These could possibly be causing some of your symptoms. Hope you get some answers.