肚子疼的英文：have a stomachache、collywobbles。

have a stomachache：胃痛；肚子疼

collywobbles：n. 肚子疼；急性腹泻

例句：

1、She often pretended to have got a stomachache after meal and sneaked out of washing dishes.

她饭后常装作肚子疼，狡猾地逃避了洗碗。

2、I have a headache and a stomachache.

我头疼，肚子也疼。