Wilderlife
WKR
Squats and deadlifts. Look up starting strength. Buy the blue book. Read it and do the program as described. It will change you forever. Very few people do it though.
This!
Lots of exercises may help with mobility, conditioning, flexibility, etc.
BUT, if you look at this situation more simply - you need to get stronger. Some people hate the idea of being a 'gym junkie', but honestly, some basic barbell training will change your life. If you drive your squat and deadlift up to a decent baseline level of fitness, everything in your life that requires physical effort will get better, and your lower back will certainly improve.