There are many pain related symptoms associated with CRPS types I and II. Burning/Freezing pain is just one of them others are lancinating, electrical shock type, bone crushing, like a knife is being twisted in your limb, being stung or stabbed by sharp needles etc., relentlessly!! That being said pain can wax and wane although in CRPS it never goes away (with the exception of remission) and when a flare hits (not unlike the flame of a fire that suddenly burst/increases) the pain suddenly increases. A flare can last for minutes, hours, days and even become the new baseline for the daily torture that CRPS can cause.

Having a "flare" is not diagnostic of CRPS because many other things can cause someone to have a pain flare. Osteoporosis for instance, can cause pain and eventually pain flares.. as does many other things.