Speaking from my own experience, my back problems in my early twenties were caused by being weak as f***. My muscles were literally too weak for every day life thing like standing up straight. I would try to hold good posture but it hurt after like a minute. Building muscle and getting stronger fixed this permanently. Sure, some people do genuienly have spinal issues, but my non-professional opinion is that the majority of people can fix or at least significantly improve back problems by just getting stronger so that supporting your body is super easy for your muscles.