Upper cheek / lower eye area twitches after smiling and or yawning. it has been happening for 3 weeks now. no pain. should i be concerned?

Probably not: These may be benign fasciculations, possibly exacerbated by caffeine consumption. Most of the time these resolve spontaneously. However, this might represent the earliest symptoms of a condition called hemifacial spasm that might require further evaluation & treatment. The passage of time is the only way to answer that question.

Myokymia : Not at all Thomas. This is benign and known as myokymia. It's sometimes associated with taking caffeinated beverages.