Let me just preface this by saying I have a chronic pain disorder that targets my back already. I've been binding for about a month now, not every day tho, and while some days I'm totally fine, other days I get really bad back/rib pains. I'm quite small chested and the binder isn't too small. I don't think it should be hurting like it does, but I very much prefer it to sports bras. Any advice? :help:
The only relief I have found from binder pain is to wear it less, even if that means not wearing it much at all. I see you're in Florida. It might be harder as summer hits, but if you can, layering helps a lot, and wearing darker colors on top. Depending on where the pain is (or if you have exercises for your preexisting back pain) strengthening can help, but you have to be diligent about it.
It's not supposed to hurt. Given your chronic pain disorder, I wouldn't be surprised if you're naturally more sensitive to the stress that binding puts on your body. Since not binding at all is not a fun solution, I would just advise that you be careful. On days when it feels fine, that's great. Keep it up. On days when it hurts, take it off and just wear a sports bra. If you leave it on when it's hurting, it could be doing damage. As long as you're careful and take it off when it hurts, you should be fine.