The most common and most likely answer to this crossword clue is the 6 letter word THROES
T
H
R
O
E
S
More clues leading to the result THROES
Buddy explains!

The straight part
We know that "pangs of suffering" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pangs of suffering = throes.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does THROES mean?
THROES noun- A pang, spasm.
- (usually plural) A hard struggle.
- A tool for splitting wood into shingles; a frow.