If I were in your shoes (and I pretty much have been), I would strive to get in the best shape of my life. Carrying extra weight is a killer as is having a weak core. There's been lots of proponents of stretching but I am a much stronger advocate of strengthening. There was a time when it would take me 15 minutes just to get out of bed each morning. The thought of going to the gym was a joke. But once I started some rehab, the harder I went with strengthening my core and eventually lifting heavy all over, the better I felt. Sure, I started with LOTS of core work, McGill Big 3 is a great place to start along with walking 10-15 minutes 2-3 times a day. But that graduated into competing in powerlifting competitions and deadlifting 600lbs earlier this year as a 55 year old. And my back has never felt better.
And those little inflatable lumbar supports for your car is also super valuable. Seems like car seats are about the worst possible aggravators of lumbar issues.
