I'm not a guru, but I've made connections with some people who know stuff.
General philosophy boils down to, if you have chronic back pain, it only really gets better by strengthening the muscles in the area.
Try some dead hangs (hang on a bar with everything relaxed except for your hands) for as long as you can.
Do some back extensions (in good form, don't press range of motion to where it hurts).
Other core/back exercises can be good to, but those are a couple of the most targeted.
Do a couple sets 2-3 times a week (don't overdo it, the recovery is what fixes things), and you should see some results.
I didn't have any major back issues, but had some occasional stuff, and this kind of work helps.