Chest pains and shortness of breath

I've always had chest pains and shortness of breath. Sometimes the chest pains are sharp, stabbing pains, sometimes they're dull pains. Sometimes they hurt so much I can't breath. The shortness of breath doesn't have any pain that accompanies it. I just feel like I can't catch my breath. I try to take deep breaths, and it still feels like I'm not getting enough air. Sometimes these symptoms last a few minutes, sometimes, a few hours.

I am 23 years old. I'm 5'5", 145 pounds. I do smoke, but its only been the last few years. These symptoms go back as far as I can remember. I know smoking doesn't help. When I was 14, the doctors diagnosed me with Mitral Valve Prolapse. They basically told me it wasn't bad enough for medication and unless things worsened severely, there was nothing I could do. When I turned 18, I went to a heart specialist, and he ran all the same tests on me, and told me it wasn't MVP, and that it was actually acid reflux and prescribed some acid reflux medicine (the purple one, I can't remember the name). I took this medication for a while, and after having no relief, I stopped. I haven't been to another doctor since. Besides the fact that I don't like how condescending some of these doctors are, I do not have health insurance or the money to go. My boyfriend suggested it may be asthma, but I'm not sure that's a possible answer either. The bulk of the symptoms happen when I'm being still and completely inactive. I've had a couple instances in the last month where I felt short of breath at school, but mostly its been when I'm at home. I know I need to go to the doctors as soon as I can, but if someone could just push me into the right direction, I'd be so appreciative.