pressure in middle of my chest I have mitral valve prolapse

I'm a 42 year old, relatively healthy female. Two years ago I had a cardiac ablation for pvc's, and this past July I had another electrophysiology study done which showed no recurrence. For the past few days I've had on and off sharp pains in the middle left side of my chest. It's not associated with deep breaths or physical exertion, it just comes and goes, sometimes makes me dizzy. Yesterday I had a slight pressure in the middle of my chest that lasted almost an hour. Today I'm still having the pains in the left middle, on and off. I know that I have mitral valve prolapse with slight regurgitation. Could this be a symptom of that? I have an appt with my cardiologist first thing tomorrow morning, but the nurse told me to go to the ER immediately if I get shortness of breath, a heavy pressure, or the pains do not go away as they have been.