Final answer:
The client's response about a bad day with chronic pain is an example of Sustain Talk, which is communication that implies maintaining the current state rather than changing it.
Step-by-step explanation:
The client's response to the coach's inquiry about what a really bad day looks like in terms of living with chronic pain is an example of Sustain Talk. Sustain Talk refers to the client expressing reasons to maintain the status quo or reflecting resignation to their situation, without any indication of a desire for change. The client acknowledges the ongoing presence of pain and appears to accept the likelihood of increased pain as he gets older, demonstrating a certain level of resignation about his condition.