A stiff lower back is one of the most common things people mention to me, and it’s rarely fixed by one heroic stretch. What tends to help is small, regular, unremarkable movement.
Change position more often. Backs generally dislike stillness more than they dislike activity. If you’re at a desk, standing up every half hour or so is often more useful than any single stretch you could do at the end of the day.
Move your hips, not just your back. When hips are stiff, the lower back often ends up doing their work. Gentle hip circles, or simply rocking your weight from foot to foot while the kettle boils, can share the load more sensibly.
Breathe into it. Sounds vague, but it isn’t. When something aches we tend to brace and hold our breath, which adds tension to a body already asking for less. A few slow breaths, letting the ribs widen, genuinely changes how the area feels.
One honest caveat: if your back pain is severe, persistent, spreading down a leg, or came on after an injury, please get it properly assessed rather than working around it. That’s exactly what a physiotherapy appointment is for.