I thought I had a problem with my back. My doctor examined me and said it's not my back, but that I have a sacroiliac dysfunction. What is a sac

Sacroiliac pain. Sacroiliac dysfunction : where your spine end , that is sacroiliac area, s1-2-3.....The joint abnormalities produce pain lower back similar to sciatica, pinch nerve, radiculopathy, or disc hernia. That is related with abnormal motion and fixation, and the diagnosis is at examination and mri.
Sacroiliac! Most sacroiliac pain comes from sacroiliitis, which is an inflammatory condition and not treated by Aleve (naproxen) type drugs alone. See someone in rheumatology! certainly you need an ap-pelvis xray!