Back pain can either be upper, middle or lower. However, most people tend to suffer from lower or upper back pain.
Then again, barring cases of slipped disc, the majority tend to collect stress and tension - and resultant pain - in their upper backs.
The regular yoga practice will go far in relieving the stress and tension that sometimes cause back pain.
In fact, studies have shown that Yoga is the number one, most effective way of relieving back pain. Then again, not all "Yoga poses relieve back pain. Some can even aggravate existing pain. This is why it is important to know which poses will be most helpful in relieving back pain.
It is best to do these practices under the supervision of a certified Yoga instructor. If you encounter any problems, you should consult an expert. Even just one or two sessions with an instructor will help. An instructor can help you very much with your form and posture during asana practise.
Here are some of the best yoga poses and for relieving back pain. Each asana can be held from five to ten seconds. This again, depends upon your level of comfort. Remember, all Yoga practices should be done on a mat or other soft, supportive surface.
Asanas: Tree pose Fish pose, Wind Releasing Pose, Sage Marichi twist, Locust pose Half moon pose and Corpse pose.
Breathing Exercises: Mild Kapalabhatti, Anuloma-Viloma
P.S.: Avoid all forward bends, even under normal circumstances.
Also avoid rigorous, strenuous work and exercises such as Sun Salutation.