"For six months now, every evening my stomach hurts (my guesses). It s…

"For six months now, every evening my stomach hurts (my guesses). It starts to rumble and then it poops, that's every evening we start feeding him. I thought maybe it was because of that, but I don't give in to any tantrums. There were thoughts that it might be teeth because when he chews on something it calms down, but the crying and pooping worry me. Could it be something with his stomach? "