heart health advice to pain

I am wondering if anyone knowledgeable about heart disease can help me b/c my narrow minded doctors refuse to. I have been to three doctors, one being a cardiologist. I am 23 and have had chest pain under my lower left bra-line of my chest for the past 4 years. I have had an EKG and Ecco done but only thing that has shown up is mitral valve prolapse which my doc. say is minor….My pain can be very severe to the point I am scared I am going to die in my sleep…it wakes me up in the morning mostly and is hard for me to get going in the morning or when I exercise or sleep on my side…the pain sometimes is in my left side of my back too….the pain in my chest though feels like blood is trying to pump through but can’t and this terrible pressure, pinching, sqeezing feeling….My brother who is 21 has the exact same symptoms I experience to a T….we have had numerous conversations about this and it is so frustrating b/c doctors tell us that it is asthma, pulled muscle, stress or lung pain…It is very aweful b/c i keep wasting money going to the doctor and getting the same answers….the pain is worst w/ alcohol, coffee, salt and exercise, stress…i try to avoid all as much as possible which makes for a pretty boring life…anyway, if anyone has any advice or can relate to this I’d so appreciate some feedback b/c i’m too young and so is my brother to live the rest of my life like this. Thank you for any feedback!