American registered nurse Margo McCaffery, a pioneer of the field of pain management nursing, famously had a theory about human pain: "whatever the experiencing person says it is, existing whenever he says it does".
Almost all of us, at some point, will strain or irritate a muscle or ligament, and the resulting pain can have a big impact on your daily life. To make that pain subside is it better to use ice or heat?
In an age when it can often feel like every moment of the day is scheduled to the minute, workouts can get tossed to the side. Even worse, trying to continually force exercise can quickly cause self-motivation to evaporate.