Comes to again and feels pain (7)
I believe the answer is:
reaches
'comes to' is the definition.
(I've seen this before)
'again and feels pain' is the wordplay.
'again' becomes 're'.
'and' says to put letters next to each other.
'feels pain' becomes 'aches' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
're'+'aches'='REACHES'
Can you help me to learn more?
(Other definitions for reaches that I've seen before include "Succeeds in achieving" , "Hands down" , "River stretches between bends" , "Arrives at" , "Bays" .)