I suffered a lot of lower back pain, and eventually it was proved to be due to posture.
In particular it improved dramatically when I changed my car. The seat in the old one didn't give enough lumbar support.
Try putting a bolster, or rolled up hand towel behind your lower back when seated. This will not only push your lower back forward to create the S shape needed, but it will also remind you constantly to think about your posture.
Also analyse the seats you regularly use to see if they give enough lumbar support. Have a look in an old peoples home at the chairs the elderly use for inspiration.
Painkillers will only mask the symptoms, not improve the condition.