Last night I suddenly started having pain in the lower left side of my abdomen, near the hip bone to…

Last night I suddenly started having pain in the lower left side of my abdomen, near the hip bone toward the center. It feels like a sharp ache when I move. The pain hasn’t gone away overnight and it’s still there. I’ll see a doctor tomorrow. I don’t have any other symptoms. My bowel movements are normal, but not frequent. What could this be?