I was a preemie born at 25 weeks. i had tiny holes in my heart and murmur that i no longer have. over the years i was investigated thoroughly for palpitations that turned out to be benign. am i high risk for heart issues or murmur to come back ?

The tiny holes you cite likely represent common defects that seal over as the heart finishes forming. The other murmur (PDA) stops when the structure self closes or is fixed with a procedure. Your risk of hear issues are more related to your genes (family influence) and lifestyle than your prematurity. Live life, follow doctors recommendations and don't dwell on your difficult start.