A large percentage of humans have lower back pain due to a number of different reasons. Most look to get the back fixed or stretch out the hip flexors to help loosen up the lower back and relieve pain.
Well guess what? You're doing it all wrong. See, our body is full of systems that keeps us in-sync. When one system is weak and not used much, the other systems have to work harder to create compensation, which leads to the pain you feel as a result of that.