hi, im 41 years and ive had an isolated lower back pain, emanating from the left side of my sacrum for many years now, maybe 10 years. iv just had an xray and have to wait two days to see the doctor. but in the xray are two dark spots about an inch across, one over my sacrum and one off to the right side. i know i have to wait to see my doctor, but what could these dark shadows represent? thankyou kelly