I had left side lower back pain for more than two years. I never bothered about it too much but noticed it was increasing. Went to see a doctor who recommended an xray at first. Nothing untoward was seen. Then he sent me for an mri. Saw a mild bulge at L4. Sent me to physio. They recommended no gym and few exercises. The superman and head raise while lying in stomach. Followed by icing. I also did electrical therapy. Now the pain is near zero. It took about two months doing exercise at home too. Stick to it the pain will lessen.