Subsequent to getting a root canal done it hurts to apply suction with my mouth to the tooth or to lick the top?

It's due to cavity: Most likely this was due to the cavity in the tooth and the action of the air across the cavity caused this discomfort.

It is possible: During the root canal therapy a lot of collateral tissue (gums, nerves, muscles) damage is done. The pain is a symptom of the affected tissue inflammation. Over the counter medications (Tylenol, Advil) for a few days will ameliorate the pain their anti-inflammatory effect. If concerned, call your dentist for post-op exploration.