Lumbar Compression & Strengthening Plans

So I’ve been snooping around the forums looking for advice on this but can’t seem to find too much on specific programs - so I figured I’d ask.

I’m a 17 year old male with some sort of lumbar compressiony thing. I don’t quite have the funds to go get an MRI, but I’m not in any sort of severe pain so I can manage. When I was lifting a few years back, I was a skinny lad of 125 lbs at 5’8 (185 Bench, 285 squat, 335 deadlift - pretty meh). I was given the “advice” by my school trainer to not worry about training abs because squats and deadlifts were more than enough. I just nodded my head and kept going as I had okay form. One thing I noticed was that my lower back used to hurt when I was starting my workout, stopped hurting during, and hurt whenever I used to hang from a pullup bar.

The pain persisted after I stopped lifting to focus on tennis, and I haven’t grown since 8th grade (father is 6’ 1") so I figured if I could relieve the stress on my lower back I could regain some of the disc height and overall spinal health.

I’d like to get together a routine that focuses on lengthening the spine, strengthening accessory muscles, and stretching overactive muscles. What stretches and exercises would you recommend that I do or avoid?

Cheers, and happy new year!