Am I right to think that MD's really won't pay attention to me until something big (like passing out) happens? (read on...)

So, as I’ve said a couple times before, I have some undiagnosed medical problems. Lots of trouble getting a full breath, headaches, dizziness, sharp pain in my chest, all that. Well, I’ve gone to 3 different doctors and I’ve gotten three different answers:
“Could develop into asthma. Call me if it gets worse.”
“It is asthma. Here’s an inhaler.”
and
“Allergies. Here’s some $100 pills that won’t be covered by your insurance.”

Nothing we’ve tried (which includes some…less-than-traditional ideas) has helped. The inhaler and pills worked for about a week, but then did absolutely zilch.
From the conversations we’ve had with different people, I get the feeling that nobody’s going to really pay much attention to me unless it’s obviously “big” – if I pass out or really can’t breathe or something.
Since asthma is getting so common, people just off-handedly call it asthma and move on with their life. But I keep saying, the inhaler doesn’t work! My mom believes me, and she’s trying to figure out what’s wrong with me. We’re paying attention to everything I eat, writing everything down, all that. But I have a feeling no doctor is going to read through everything I ate all week. So…What should I do make a Dr. pay attention to me? Does it really have to be dangerous for people to think about you?

Sorry if this is kind of confusing. I’m kind of tired and I’m kind of mad about other stuff.