Are there any cases of someone who has a hole in their heart with no heart murmur?Or am i the only one?

I lived a complete normal life. Throughout my childhood I was really active and always playing sports and was even a tri-sport athlete (vball, bball, softball) in highschool. I had no signs of tiredness or anything. Then one night when i came home i had turned on the light in my room, but something wasn't right. In part of my eye (peripheral vision of right side of both eyes) it was still dark. Confused, i took out my contacts, but they weren't dirty and the blindness was still there. Long story short, i went eventually went to the ER and they had found that i had a stroke at 18 years old. Totally shocking. After they ran some tests, they found everything was normal but i did have a hole in my heart....and shockingly I have never had a heart murmur. The doctors have never seen a case like mine. & were shocked that the hole was never detected and that i have no murmur. & also i had just recently started taking birth control so, there was no proof to rule it out that the pill was the cause, but def. a possibility!