。
She went to school even though her right leg hurt.
Literal
She [topic-は] right leg [subject-が] hurt [despite-のに] school [to-に] went.
~のに ('despite, even though') is one of the strongest Japanese concession markers — slightly emotional, often carrying a note of surprise or mild reproach about the contrast. Here it sets up the unexpected pairing: pain in the leg vs. going to school anyway. Pain expressions in Japanese typically use the が-marker for the body part — 右脚が痛い literally 'right leg hurts.' This が-subject pattern for sensations is regular: 頭が痛い ('head hurts / headache'), お腹が空く ('stomach is empty / hungry'). 学校に行く takes に for the destination of a habitual movement.