I have had constant headaches for three weeks. is it likely to be a tumor?

Not good, not bad: The chances of a 3 week headache being a tumor are low. However, a constant headache for 3 weeks is way outside the normal range for routine headache. It could be hypertension, an abnormal brain blood vessel, stress, lots of things - but 100% you need to get it checked out. Now. Good luck. You're 19 - if you're taking crazy supplements or hormones, this could certainly affect the opinion.....

Unlikely: There are many causes for headaches. Headaches associated with brain tumors often have typical characteristics, like in the morning, associated with nausea, sometimes blurred vision. I would recommend seeing your physician and having a thorough evaluation for your symptoms.

See below: A tumor is possible but many other causes are possible. See your pcp as soon as possible.

Headache: Brain tumor is an unlikely cause of headache. More commonly, the cause of your headache is stress or tension. With a brain tumor, other symptoms usually occur also like visual changes.