Welcome to healingwell.com. A lot of people start getting headaches in their teenage years, some due to stress but a lot of the times it is a change in horomones that will "trigger" or set off migraines. I definitely would see a doctor and make sure there is nothing more serious going on that you just can't see.
I, again, highly doubt the presence of a brain tumor. You would have other symptoms and rarely are headaches a sign of brain tumor. As far as waking up saying something like you have a brain tumor I would imagine is not too far fetched to FEEL like there is something really wrong. I know this sounds weird but when I have a really bad headache I dream that I have been shot in my head or stabbed etc.
See a doctor and let us know how things are going.
I would definitely recommend going to a neurologist that specializes in headache and migraines. This is from the Mayo Clinic website:
Migraines are a chronic disorder, but they're often undiagnosed and untreated. If you experience signs and symptoms of migraine, track and record your attacks and how you treated them. Then make an appointment with your doctor to discuss your headaches and decide on a treatment plan.
Even if you have a history of headaches, see your doctor if the pattern changes or your headaches suddenly feel different. See your doctor immediately or go to the emergency room if you have any of the following signs and symptoms, which may indicate other, more serious medical problems:
I'm sorry you're doctor didn't respond very positively to the request for scans. Is this your general practioner? If you're not already, as already suggested, it is a great idea to keep a headache/migraine journal to keep track of what is going on and when. Perhaps it is also time to get a second opinion. visit a neurologist who specializes in migraines/headaches, who may at least be willing to order the scans and look a little deeper into the issue.