I have an old back injury (irritated discs in my lower back and some nerve issues) that flairs up here and there. Stretching and exercise definitely help, and most days I can ride without issue, however I would like to look into different back support options for whenever I start competing again. I need something that won't be bulky or limiting. Any suggestions?

Nobody uses anything?

i also have had back issues recently from a bad fall. Ive started using the Airowear charles owen The Shadow back protector, and its amazing!
provides a good brace and support for the back and flexibility on the front, easy to move around in for dressage or jumping.

Its pricey, but for me it was 100% worth it.

you can also put it under a show jacket or a coat without it being at all visible

Although I've never used anything myself, I'm 100% sure I've seen equestrian back braces sold. Mostly in the vein of "use this to sit up straight!" But they could certainly be repurposed for your needs.

I'll definitely look into that! I work colts and do western events, primarily speed, and with that have a slightly more relaxed posture and a different style of riding then most English riders, I don't slouch by any means but I've been worried about one impeding the way I need to ride if it's specific design is for an English seat. If that makes any sense? I'm horrible at explaining lol.