The best way to avoid back pain would be following the right biomechanics during exercise and activities. It is said that even a safety pin is enough to hurt your back if you lift it from the ground with improper biomechnaics in the movement . What exactly you should be doing? You will have to squat to lift any objects that are on the ground regardless of its weight. "Better be safe than sorry" The above image shows the way you will have to lift weights. The correct posture during activities makes you and your muscles more safer.