a nagging pain的用法和样例：
- I've got a nagging pain in my lower back.
- He survived the accident, but the injury left him a nagging pain ever after.
- I have never seen a nag like this one.
- Sue has a nagging husband. She calls him a pain in the neck and a.
- Despite this, there is still a nagging concern.
- A broken-down or useless horse; a nag.