I'm not wearing too small of a binder, it's the exact right fitting size. It's an ultimate compression binder from underworks in the size small.
I'm starting to also think it could be from my other binder type top, it's more of a sports bra but works as a binder, also another one from underworks. I exercise in it, and I've getting the pain all around the front part of my ribs (where it would cover for the most part) so I'm starting to believe it could be that.