Are you seeing improvements with what you are doing?
Do you sit alot?
Or sit for long periods of time?
Could be impacting factors.
You could have damage or irritation to a disc.
Have you had someone take a look at your squat and deadlift technique/mechanics?
Correcting how you move where this is what is causing the pain is key.

What is the issue in your low back?
Have you watched episodes which address the low back?