If you've been stretching your lower back every day hoping it'll finally loosen up for good, here's what's probably actually happening: you're not dealing with a tight muscle. You're dealing with a guarded one — and those aren't the same problem.
When your body senses instability somewhere in your spine, it does something protective: the surrounding muscles tighten up and hold that position, not because they're short and need lengthening, but because they're bracing to keep you stable. That tightness isn't the problem. It's your body's response to the problem.
Stretch a guarded muscle, and you can force it to release for a few minutes — which is why it can feel better right after. But the underlying instability that triggered the guarding in the first place hasn't gone anywhere. So the muscle re-tightens, usually within hours, sometimes worse than before, because now it's compensating for instability and recovering from being forced open.
This is why so many guys stretch consistently for months with zero real improvement — sometimes even feeling worse. The tightness was never the actual issue. It was a symptom of your spine not being properly supported and stabilized, especially during the one stretch of the day your body can't control it consciously: while you're asleep.
Fix the alignment that's causing the guarding in the first place, and the muscles have no reason to keep bracing. That's the difference between temporarily forcing a release and actually removing the cause.