Your back is working in combination with the rest of your core and your glutes, hip flexors, hamstrings and quads for optimal performance. If you have weakness or imbalance in one of those areas, you can develop back pain. Your best results come when you target all of those areas.
Exercise #1: Lying Glute Stretch
Lie face-up on the floor with your knees and hips bent. Cross your right leg over your left so that your right ankle sits across your left thigh. Grab your right knee with both hands and pull it toward the middle of your chest until you feel a comfortable stretch in your glutes. Hold for 30 seconds, then repeat on the opposite side.