What causes one leg to become a bit shorter than the other? chiro said one of my legs was shorter then he adjust my low back/hips than i feel better!

Likely incorrect: They never get long-leg films. Most of the time it's a perceived leg-length discrepancy (lld) over a true lld from a pelvic obliquity. That's a common diagnosis of theirs and when i measure patients clinically that have been told that, I have clinically been unable to appreciate a true lld.

Pelvic Obliquity: Comparative x-rays with a metallic ruler in the x-ray field proves whether is truly short or factitious due to pelvic girdle obliquity, which is the most common explanation.  pelvic obliquity can arise from sacroiliac joint (sij) instability secondary to sij ligament injury, diagnosed by means of several provocation maneuvers reported in occupational disabilities guidelines.