As the other commenters have noted, there are definitely things you can do. I had to give up playing for ten years due to back issues, including two surgeries, and thought I'd never play again. You need to work on the problem actively, in other words try different approaches and see what works for you. In my case, the following has been effective and has allowed me to resume full-time playing.
1) I use a "Dynarette" cushion plus a low footstool, and sit on a relatively high stool with a back. The back has a lumbar support cushion so that I sit far forward on the stool but the cushion supports my lower back.
2) I am careful to break after every 45 minutes or so of playing for at least 10 minutes. You can use the "Pomodoro" technique to help this during practice. If performing, be sure to take a break each hour.
3) I experimented with many guitar supports. I won't use suction cups on a good guitar, and am reluctant to install magnets. The other options all have various pros and cons, but eventually I have settled on the simple system I'm currently using, i.e. primarily relying on a cushion.
4) I experimented with many different instrument positions, and currently play with a very neck-up cello-like posture.
5) I monitored my own position and kept adjusting when I found any strain, numbness, tingling, etc.
6) I sometimes find a strap to be useful, in addition to the other posture aids. When playing an archtop for non-classical playing this is what I prefer. I use a conventional strap with endpin and heel buttons (this requires modifying your guitar, of course, which in my case I was will to do). The "around the neck into the soundhole" strap was not useful for me.
I went through most of this analysis several years ago as I was rediscovering the instrument, so I may have forgotten some steps; if so I'll update this post. The key points are: Don't ignore your back problems because they will eventually force you to stop playing, as they did with me. But with some experimentation, you will probably be able to come up with a system that works. It will require retraining yourself, and that won't be trivial. For me it's been like climbing Mt. Everest, especially after a ten-year hiatus. But it has been worth it.