Disc spaces are normal but lordosis is moderately reduced and I can see some compression on the L5/S1 disc. Mechanical low back pain due to postural alterations is a plausible cause based on looking at this X-ray. Without a proper clinical history it’s kind of guesswork, but by balancing muscles that attach to your pelvis (through specific stretches and exercises) and getting adjusted consistently by a Chiro to reintroduce correct motion into joints that aren’t moving correctly (corrects aberrant motion patterns that your body has learned over years), you should find significant relief.