This is a video of a two-legged dog, having great fun at the beach.
As summarized by distractify.com:
Duncan Lou is a young boxer discovering the beach for the first time. He happened to be born with two deformed legs, which were removed as a puppy. He has a wheelchair, but he hates it. So instead, he runs full speed unassisted with his two unstoppable fore-legs. When you see him gallivant across the beach, you'll understand. Duncan is pure courage.
So, tell me again how a slight leg length difference or an barely perceptible spinal joint “misalignment” is the cause of someone’s terrible back pain? Biology is fantastically flexible. Minor biomechanical variation is never at the heart of any common, serious pain. In fact, even major ones are often handled gracefully: in dogs or people. Which is not to say that a pup like Duncan Lou won’t grow up to have some pain (he probably will), but it puts minor biomechanical glitches in perspective.