Kneel, then push your hips back toward your heels
Reach your arms forward and lay your hands flat on the floor
Breathe into the stretch
Just make sure you decompress your spine first. You can do this by hanging from a pull up bar and dangling your feet to touch the floor. You'll feel your spine extend, this is what you want especially with back pain since it brings pressure off that nerve.
Putting your elbow out onto the wall *shoulder height*. Then place your feet away from the wall. The end position should be you leaning your hips tword the wall until its under your shoulders. Dont be afraid to stick your hips out more to get more of a stretch.