Pacer lost? Trouble in chest muscles? (9)

I believe the answer is:

pectorals

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'chest muscles?' is the definition.
'pectorals' can be an answer for 'muscles?' (pectoral is a kind of muscle). I am not sure about the 'chest' bit.

'pacer lost? trouble' is the wordplay.
'trouble' indicates anagramming the letters.
'pacer'+'lost'='pacerlost'
'pacerlost' anagrammed gives 'PECTORALS'.

'in' acts as a link.

Can you help me to learn more?

(Another definition for pectorals that I've seen is " Muscles".)

I've seen this clue in the Sydney Morning Herald.

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