Chronic back pain here, eventually needing surgery in 2019. Now minor discomfort on the bike, it's real like that makes it worse.
For me, what has helped is daily exercises and stretching and especially paying attention to posture, how I sit (no slumping!) and to keep moving. Matching a movie at home, for example, I get up and stretch every 10-15 minutes. Limiting gardening activity--you're never done, so just do more tomorrow.
Actually, it just feels best when I am on my bike.