My sister had been experiencing horrible back pain that traveled down to her legs. Her doctor diagnosed her with sciatica.
After reading this, I think I know why she may have developed so much pain. She fell and broke her tailbone as a young child. She might be experiencing coccydynia as well as sciatica. Either way, since the tailbone and the sacral region are connected, I imagine her pain travels between the two.
She went to see a chiropractor, and he did relieve her of some pain initially. However, the pain seemed to return and require frequent visits, so she stopped going.