It isn’t hard to stop compressing the bones of the lower back once you realize how often you are compressing them when walking and standing. When we are sitting we tend to do the spine an opposite disservice by rounding too far backwards.
The spine is comprised of 25 bones in four sections. Two of the sections curve out— the sacrum and thoracic (the middle back or ribcage) and two curve in— the lumbar (lower) and the cervical (the neck).
There is a very delicate balance in the design of the spine. The lower back and neck are meant to have the exact same 
degree of curve and they should be aligned vertically in space—a plumb line should pass directly through the middle of both of these curves.
Unfortunately this is rarely the case though one of the more interesting aspects of alignment is most people perceive themselves as standing up straight even though they are leaning backwards slightly.
This is a fascinating conundrum because so many people could alleviate their back pain almost instantly by simply becoming aware that they are compressing the bones of the lower back when standing and walking.
Look at the picture of the lumbar spine and see how much space there is between the bony projections that come off the back of the spine, known as the spinous processes. The arrangement of these lumbar bones is such that you can bend freely forward and bend/extend backwards quite a way as well. Compare the spinous process in the rest of the spine and you can see that they afford much less room for backward movement, particularly the middle spine which limits movement to protect the heart and lungs.
Everyone tends to lean backwards slightly though we don’t notice it as such, and are therefore compressing the bones of the lower back as well as throwing off the important balance of the lower back and the neck.
If you think you are standing up straight you wouldn’t think you are compressing the bones of the lower back. If you can figure out how to acknowledge in your brain that you are in fact leaning back, rather than standing up straight, good things can begin to happen.