I disagree with flobadob.
If you drive a lot, have your seat tilted back a little. If the seat has poor lumber support, put a bolster behind your lower back.
Having the seat upright means all your upper body weight is pressing down on your lower spine. Having the seat tilted back a bit transfers some of that weight into the backrest.
I suffered a lot of lower back pain, and much of it was relieved when I changed my car. I hadn't realised how bad my posture was in the poor car seat.
The way you sit has a huge effect on this problem. If you want to see a great seat for lower back pain, go into a good old people's home and look at the chairs that they have.
What you need is good lumber support that pushes your lower back forwards and prevents slouching.