I've Been Experiencing Episodic Heart Pounding For The Last Two

I've been experiencing episodic heart pounding for the last two years. My pulse is normal. I've had two cardiac work-ups and all findings were WNL. All labs were also WNL. I'm on Benicar for blood pressure, which is well-controlled, and Serevent snd Flovent, 1 puff of each daily, for asthma, which is also well-controlled.
I also occasionally feel edgy or jittery, worse in the morning.