I completely understand hun, it's so frustrating. About a year ago, I started getting migraines, really bad, so much so that I would have to go to the E.R. For morphine. They couldn't tell me why I started getting the migraines, they even went as far as to tell me that it could be a possible tumor, an anerissum (sp), or even viral meningitis, luckily it wasn't any of those. I still suffer from migraines, but none like they used to be.
You're boyfriend should be more understanding, if it's not something you can control, then HE should be the one sucking it up. I'm sorry to say it, and I hope I don't offend you, just callin it like I see it.
What about a catscan or MRI of your lungs? They havent taken any x-rays or anything? I had blood clots pass through my heart and into my lungs, I believe they used a catscan to check my lungs for that.
Maybe an ultrasound to check for an ulcer? Allergies are something you can develop over time. I wasn't born with seasonal allergies, but now, it seems that I suffer all summer long.
I NEVER second guess about going to the dr, heck, I'm paying MY bill, so. I just wouldn't feel bad about going to the dr's so much, this is why you have insurance, and pay your bills. They're there to help you, and I would insist on them running some more invasive test, because obviously what they are doing just isn't cutting it.