Before you begin any exercise program and before you attempt any Yoga postures you need to see your doctor, especially if you have chronic pain, to further determine the cause of your pain. Some Yoga poses including forward bends and backward bends are not suitable with certain persons, with certain spinal injuries, and are not suitable for pregnant women. For example, you should not attempt deep forward bending if you know that you have very tight hamstrings. Your hamstrings are pulling your pelvis in a certain direction and when you bend forward and you try and counteract the pull of the hamstrings it's not going to work. All it's going to do is force your pelvis into a very unnatural position. It's not going to stretch out your lower back and all it's going to do is cram those bones together. Those vertebrae are going to be compressed and you're going to cause yourself more pain and more damage to your body. You need to go slowly, you need to work up to these poses and I'm going to show you how to begin instead of how to hurt yourself.