Yoga works wonders for health and fitness even if it is for back pain there are certain yoga poses that help to cure normal back pain like
1. Cat-Cow
2. Downward-Facing Dog
3. Extended Triangle
4. Sphinx Pose
5. Cobra Pose
6. Stretches etc.
Although there are many other causes for back pain like accidental issues or medical history, bad running techniques for which you should consult a running coach or fitness trainer first.