What is a stricture?

Do any of you have any "real" info on what a stricture is? I know it is when the opening to your tummy closes up, but beyond that I don't fully understand it. I don't know if I might have one or not...I am a little worried/concerned, but not to the point of freaking myself out over it. I have been having a harder and harder time getting in my liquids...it now hurts right after I swallow them, even water, and even with the smallest sip. I have vomited with some of my food, but not everything...tonight it happened with sugar free/reduced calorie pudding, and earlier in the day it happened after I tried a bite of chili. Maybe I am pushing on solid food too fast and my tummy pouch can't handle it. I have only tried soft solids...ground meat and such. If anyone has any info that would be awesome!!! Thanks so much..you all rock!!!!!