There are several options that would explain this pain:
1. A pull of the Quadratus Lumborum and abdominal muscles, due to poor sleeping, incorrect lifting or a sudden twisting motion
2. A mis-alignment of the spine, which is putting pressure on the nerves (more so when sitting) and which is causing the pain with movement
3. An infection of the kidney or uterine area, which refers into the low back and abdominal area.
