Had successful mitral valve repair 1.5 yrs. ago. now having moderate chest pain, moderate shortness of breath, no edema. could this be pericarditis?

Many causes: Moderate chest pain with shortness of breath in someone with previous MV repair has many possible causes. Pericarditis unlikely after 1.5 yrs (it's a sharp pain, often worse with lying down, sometimes pulsatile). Worsened valve leading to heart failure can cause this (SOB worse lying flat), and so can ischemia/ angina. Evaluation would include an exam, EKG and chest xray, blood tests