'pain-associated' originates from the combination of 'pain' and 'associate,' where 'pain' refers to physical discomfort and 'associate' means to connect or link.

'pain' and 'associate' have been used in English since the Middle Ages, and their combination into 'pain-associated' is a modern development to describe conditions or symptoms linked to pain.

Initially, 'associate' meant 'to join or connect,' and 'pain' referred to physical suffering. The combination has maintained this meaning in modern usage.