Back pain resists quick fixes, and yoga has a reputation for being vague about what it actually does. Trials of yoga for chronic low back pain have found that practice does better than no exercise at easing pain and improving function, though the size of the benefit is modest. That is a more useful starting point than either a cure story or a dismissal, because it moves the question from "will yoga fix my back" to "which kind of movement helps which part of the problem."
It starts with flexibility. Much lower back discomfort comes from muscles that have been held tight for a long stretch of hours. Poses that lengthen the back of the body, like Downward-Facing Dog, Child's Pose (Balasana), and a low lunge with the hands down, open up the hips and the line of the spine at the same time. Held gently, with the breath, they also give a tight back somewhere to go that is not the chair you are sitting in.
Then there is strength. Yoga poses such as Cobra, Plank, and the Warrior series build muscle around the spine rather than only stretching it. That surrounding support is what lets the back hold its shape during the rest of your day, and it is the half of the practice most people skip when they only want the stretching part.
The mind-body piece matters too. Back pain is one of those things that keeps itself going, because being in pain makes you brace, and bracing makes the pain worse. The slow breathing and attention that come with a practice give that bracing somewhere to settle. Plenty of practitioners describe their back feeling looser on the days they manage to breathe slowly, and that is not nothing.
One thing worth keeping straight: this is a months-long habit, not a week-long fix. Modest benefits that beat doing nothing still add up, but only if the practice survives a sore week. That is also why modifying matters. Pushing into a shape that hurts is how a beginner ends up avoiding yoga entirely. If your pain is sharp, radiates down a leg, or followed an injury, have it assessed before you build a sequence around it.
If you want a place to start, our free online yoga sequence builder lets you put beginner-friendly poses together in the order that suits you, and you can adjust a shape here and there rather than forcing your body into someone else's version of it. For practicing at home on Windows, Sunrise Flows is on the Microsoft Store (https://apps.microsoft.com/detail/9PN912651P7W). And a new issue of our newsletter is published on the website each month, with enough to follow along with at your own pace.