From a distance it sounds like you need someone with you at the doctors. Friend or relative. I was going to say someone who is pushy but assertive is the better term.
It sounds like they thought you were exaggerating your symptoms. OR you have a bargain health insurance plan. A plan which is slow to authorize tests.
I do. For instance, my last ER visit, I was brought in due to HBP (of course) and shortness of breath. A cough had made me pass out. I got to the ER but amidst really feeling bad - I didn't think to tell them I've had a partially collapsed lung for 6 months - it just wasn't at the front of my mind and there are a million things going on. So, they're like, "Yeah, you have the flu - that sucks - but why are you here." And all I thought to say was, "I've been really sick, breathing got a
lot worse, the blood I'm coughing up has gone from brown to bright red." It was after getting some rest the next morning that it dawned on me that I should've told them that.
So, I've been looking into hiring/finding a patient advocate to help - the number of appts I'm getting calls to setup (but then the fatigue wears me down) is so high but then I drop one or I think I have them all but miss one.
I don't have bad insurance (fortunately - or unfortunately in terms of your theories, which I think makes sense) - state employee with decent coverage. I do think that the unlikelihood of a 40 year old male with heart issues, etc makes people doubt what's going on. That said, I also have a form of muscular dystrophy and even that creates issues with some of the organs involved/symptoms but then it's not super well known so people don't connect it. Recently, I got crap from one clinician for referring to it as a form of muscular dystrophy and not its actual name. Took that feedback and then the next time I went to a dr, I referred to it via its official name and was told, "You're using a pretty specific rare clinical term - have you been searching for things online?" (No, and I have genetic testing confirmation for me, my mother, and my kids). Here's an example of how issues feel dismissed:
I was diagnosed with this form of MD after having some hip problems (which developed because of the MD), during/after HS (my mother had the same ones - so we all sort of got checked out at the same time when she had a hip replacement at age 35). A decade ago, I had a good dr (chair of ortho at Univ of Nebraska Medical) who was like, "Yeah, these are screwed up. You need help." I move (due to work and family). Try to get assistance in this community and the first ortho I went to didn't take a Hx and when I tried to give him the background, told me that my hip problems came from a fall I "must've had in HS and forgot about." Completely disregards me, even when I try to give information (tells me I shouldn't have ever visited more than one dr - ignoring that by age 35/40, it's actually fairly normal to have moved for college or grad school or something). I ended up dropping it - had other stuff to deal with. But
then - when this most recent health issue emerged - my CT scans kept showing some hip problems and I'd have ER drs come and ask, "Did you know you have major hip problems?" (Yes, I didn't say anything because I'm here about my chest, etc). But when I inform someone, it gets dismissed. It feels like that is happening here - when I have tried to point out things like my partially collapsed lung, it gets no attention. If I downplay something like that and a clinician "finds" it or mentions it for the "first time", it gets attention.
I had an old user name, many moons ago lol, and I almost forget it, it was sooo long ago. I think I changed it due to the fact of it being so close to my name, you know ? 
percent. Sending you lots of gentle hugs and warm thoughts 
