Struggling to be Heard by My Primary Care Physician

My primary care physician acts like he doesn't have time for me, and I struggle sometimes being heard. Given that our appointments are usually about my ADHD medications, bringing up my chest aches and heart difficulties for a referral will be especially difficult. For those who are further along on their journeys or may even have diagnosis: how was your experience in the beginning? Do you have any tips on being taken seriously? My problem has always been irregular and far apart, so since I haven't had life threatening issues it's hard to pick up on or prove on the spot.