Bra search nightmare

Hey I have been having trouble finding the right bra. I'm not a big girl in general but I could loose a little wait. I think I'm a 38 d or Dd. It varies depending on the brand. Is there some sort of bra guru anywhere? Cause these things are giving me back problems or constant muffin tops or both. I just need a good bra that isn't a sports bra and doesn't cost a fortune.