Hero, though not sick, experiences pain (5)
I believe the answer is:
aches
'experiences pain' is the definition.
The answer and definition can be both to do with human feelings as well as being verbs in their -s form.
Maybe you can see a link between them that I can't see?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for aches that I've seen before include "Hurts; yearns" , "Continuous pains" , "sign of suffering" , "discomfort" , "Pains, hurts" .)