I had lower back pain and sciatica type pain. My advice is first push your doc to get it imaged to rule out any deep physiological problems, but be wary. I had 2 bulging discs, which seem to have retreated. I had and still have narrowing passages in the vertebrae and collapsing discs, but that seems to be just part of aging and not a cause of this pain. Which was caused by - no one could tell me. I used a chiropractor and did yoga/stretching, building up to what I could handle (Cobra pose, Bird dog, Cat Cow, toe touching, hurdler's stretch, glute and hip cross leg stretches, hip raise from prone on back, planks). It took nearly 2 years to go from crippling pain to full relief (I was 67 when the worst of it hit). I can't tell you if it was the exercise or time. No drugs helped worth mentioning but I took a lot of ibuprofen before bed. Who knows if there was a placebo effect. BTW, long soaking hot baths help. I have 2 younger brothers who went through similar problems and the same kind of therapy. One is back to 100%, one still has some pain but is fully active (ski instructor, back packer). Get a good chair, don't skimp on the ergonomics. I got a lot of relief using a standing desk, which your company should pay for if you are a desk worker and you get an MD note. Lastly, make sure your bed and pillow are supportive. I found that one of those between the knees pillows helped me sleep longer and with less motion and pain.

Good luck!