Over their going out West, seem very pained (6)
I believe the answer is:
writhe
'seem very pained' is the definition.
I can't tell whether this defines the answer.
'over their going out west' is the wordplay.
'over' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'going out' indicates an anagram (out can mean wrong or inaccurate).
'west' becomes 'w' (abbreviation).
'their' is an anagram of 'rithe'.
'rithe' after 'w' is 'WRITHE'.
Can you help me to learn more?
(Other definitions for writhe that I've seen before include "'Twist, squirm (6)'" , "Squirm in pain" , "6, maybe in agony" , "Twist as in pain" , "Painfully move" .)