Shorts never fit me properly?

Hi everyone, I decided to come to reddit because I'm SO confused about the cause of this and what to do. So recently as summer is starting up where I live, I wore a pair of jean shorts (American Eagle Curvy Size 2) and they felt too tight. They fit, but they were tighter around my butt and crotch and were uncomfortable. So, I assumed I grew and needed a size up. I redid my measurements and my waist was a 28" and my hips 38", a 2 at american eagle is supposed to be 26" waist. I went to the store yesterday in hopes of finding some new shorts. The chart on AE's app said I was a size 8 according to my measurements, but I highly doubted that. When I went I started off with a size 4 and 6, both of these were too big. So, I went down to a size 2 and this felt comfortable and not tight, but it had a big gap in the back of my waist. So I tried a size 0. That fit nice and a little tighter, but it STILL had a gap in the back of my waist. I didn't try a 00 or a 000 because I know they won't fit over my hips/butt. Why does it do that? I've found this to be a problem at Hollister sometimes as well. AE and Hollister is where I've bought my shorts and jeans in the past. Any recommendations for places with good quality jeans and jean shorts that won't break the bank? Thanks!

P.S I know some may recommend a belt, but I'm not a huge fan of them honestly. I would like to have shorts that fit without a belt.