Back Pain when working, not when gaming for the same time. any advice?

First, I'm not a doctor. I have hard-won experience, but fact-check everything I say, okay?

Having had surgery for a L4-L5 disc herniation, and declined additional surgery for a L3-L4, my first advice is to avoid surgery if at all possible, and get it if absolutely necessary.

I agree with the previous suggestions to exercise, lose weight if appropriate, and use a lumbar support, but one thing I want to emphasize is that there is no such thing as a back-friendly, orthopedic chair.

Sure, you'll definitely find chairs that are more comfortable for your particular back woes, but sitting in one position for hours, regardless of chair design, is going to wreck your back. Bodies are meant to move (there's a reason you "...have the urge to stretch and bend"), so you have to move and change positions often. Maybe look into stand-up/sit down desks; I built one with parts from Monoprice and Home Depot and it was a game-changer.

Sarno's books (suggested by yeeter) are definitely worth a read. Personally, I got the best mileage from Dr. Stuart McGill's books. If you haven't actually herniated a disc, McGill's "Big Three" exercises (modified curl-up, side bridge and bird-dog) will go a long way to helping you keep it that way.

It took a long time for me to "re-build" my back, and involved everything from multiple-mattress trials to kettlebell swings, to a half-dozen physical therapists, but I'm finally strong again and I'm pain-free 98% of the time.

Please don't wait. Trust me on this: It's going to be WAY easier, and exponentially less of a pain in the ass, to address this now instead of after damage is actually done.