My logic here is: you dont know why or what you puked yesterday. Today you are told there is a stricture, found by the MRI. I am saying, the food you ate yesterday irritated the existing stricture and thats why you puked.

The mass or tumor didnt just appear out of thin air. Strictures are caused by constant acid irritation of the esophagus, that may turn into a cancerous tumor. Yes, sometimes cancer seems to appear out of the blue, but this is a known cause. See Barrett's Esophagus, for example.

You are probably past the point of having diet "cure" your condition. Being careful of your diet now only can maybe not make it worse, or not make food feel like its stuck.