In this one-armed, 4-week trial, participants will receive prompts to report their pain symptoms 4 times throughout the day. Participants may receive up to 4 reminders to move messages throughout the day to promote participants to engage in physical activity. The receipt of messages is randomized each day. Participants will wear a research-grade activity monitor throughout the duration of their participation in the intervention to measure physical activity behaviors.

This physical activity promotion intervention is a micro-randomized trial designed to determine the most effective time to send a message to promote physical activity among cancer survivors who experience chronic pain symptoms.

Physical activity will be measured using an ActiGraph accelerometer. Data will be aggregated into physical activity estimations (sedentary, light, moderate, vigorous, steps, etc.) using standard methods. Outcome of interest will be probability older cancer survivors are physically active in the 30 minutes following the receipt of a messaging prompt to promote physical activity.

Pain state will be assessed by response to the pain rating measured by the 11-Point Box Scale in the study app. Participants will receive a smart phone prompt to rate their pain 4 times per day. Outcome of interest will be probability older cancer survivors experience a pain episode in the 24 hours following the receipt of a messaging prompt to increase physical activity.