What causes pain in the lower back and abdomen area?

More specific. More specific information is needed, lots of disease states can cause back and abdominal pain. Kidney stones, infection, muscle strain, colitis, etc. Can all present with pain in that area. Talk to your doctor to narrow things down.
Lots of things. Musculoskeletal pain, "pinched nerve" type symptoms, rectal, gyn, lower bowel issues, other see your doc.