Hello! I’m sorry to hear about your pain, this is sadly an all too common issue. If you’re petite, I doubt you’d be any bigger than a 30 band. Victoria’s secret is definitely not the place to get fitted properly, they’re known for trying to squeeze people in their small size range so this is no surprise that your bras don’t fit.
I would recommend Nordstrom, but it’s not always 100% consistent and maybe they won’t fit you in your best fitting size. Give it a go, it will still be better than it is now! Beware of independent stores, some are amazing and some are plain terrible. Try to find online reviews, and check the brands they stock. If there is Freya and Panache, it is generally a good sign (although some amazing stores may not stock them, while some stores with poor fitting standards may have them).
The best you could do is to fit yourself. I can recommend this, this, this and this. You will always benefit from learning about bra fitting. If however you are still unsure, you can also try an online counseling at Butterfly Collection.
Does any US follower have other suggestions?
This is such a common issue for women. My recommendation is to get your measurements from an expertise store. Unfortunately, it is a try and miss possibility. If you find a qualified advisor, keep her! Bra size varies from one brand to another, but generally, you will stick with your true bra size. For example, I wear a bra size in one brand but depending on the style and cut, I may wear a different size in the same brand. Hope this helps and good luck!