The most common and most likely answer to this crossword clue is the 7 plus 4 letter word SLIPPED DISC
I've seen this crossword clue in The Daily Telegraph
S
L
I
P
P
E
D
D
I
S
C
Buddy explains!
The straight part
We know that "this brings back discomfort" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case this brings back discomfort = slipped disc.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.