I am a 43 yr old female no previous history of back problems, only mild scoliosis diagnosed when I was an adolescent. my mother however has degenerative disk disease. I have no other medical conditions/ medications . non smoker, slim. for about last 2 months I suddenly began hearing a grinding sound (absolutely no pain nor sensation, just the noise inside my body) coming from my especially lower back during some sideways leaning or twisting movements of my torso. I have always been a flexible person, sometimes done yoga in past, and never any noise, not even popping. now there is no popping and no stiffness and no pain, no hang in mobility, but this unsettling noise that makes me worry that the disks or cartilage may be damaged. the only change coinciding with this new noise is that for about the same amount of time I ve begun walking regularly, about 3 times a week for around 30-45 minutes. thank you for any comments!