I've learned to control mine by doing the opposite of a lot of this advice. Stretching my hip flexors every day has had a huge impact and when I do core work, I do a lot more lower back now. Basically, according to my chiropractor, I had a muscle imbalance, which was causing my hips to rotate and put pressure on the nerve. It still flairs up occasionally, but doesn't last very long.
This is true for most people!!!!! I have three naturally fused vertebrae and herniated discs. I was told by three dr to get surgery. Many years of incredible pain. Go see a body specialist and get your legs stretched!!! Please!! A foam roller helps me alot too. I could barely walk for a long time but after an hour and half of stretching from a pro I walked out 110%. i was severely imbalanced! don't put up with pain anymore.