Here are the completed sentences based on the given prompts:

33. Lisa sat at her desk all day, and her back hurt.
→ Lisa sat at her desk all day, and she **developed back pain**.

34. Peter had a cold, and his ear hurt.
→ Peter had a cold, and he **had an earache**.

35. Emma didn’t eat breakfast, and her stomach hurt.
→ Emma didn’t eat breakfast, and she **felt stomach pain**.

36. Tim fell off his bike, and his leg hurt.
→ Tim fell off his bike, and **he injured his leg**.