YOU SAID:
She is a bear with a sore head.
INTO JAPANESE
彼女は頭が痛いクマです。
BACK INTO ENGLISH
She is a bear with a headache.
INTO JAPANESE
彼女は頭痛の種です。
BACK INTO ENGLISH
She has a headache.
INTO JAPANESE
彼女は、頭が痛い。
BACK INTO ENGLISH
She hurts her head.
INTO JAPANESE
彼女は頭を痛めます。
BACK INTO ENGLISH
She hurts her head.
That didn't even make that much sense in English.