What could be causing my child's abdominal pain around the same time every night?

Is there any tension in the house? Particularly at bed time? It could be many things, but your pediatrician is the best person to direct this question.

No tension. I think he hadn't been moving his bowels often enough. Yesterday I gave him an extra helping of greens and apple juice. Needless to say he slept through the night.

What is his eating schedule like? How old is he? What is he eating during the day? And before bed? Is he using the bathroom before bed?