a pain-killing drug的用法和样例：
- The abuse of pain killing drugs will deaden the mechanism in the body that alerts the brain to the fact that something may be wrong.
- I've got a pain in my left side.
- We've missed the last bus what a pain!
- Apple polishers are a pain in the neck to conscientious teachers.
- I have a pain in the lumbar region.
- She had a pain in her right side.