If you don't have a runny nose it still can be a sinus infection. This is exactly what it sounds like. The holes that drain your sinuses can become closed off enough that no secretions/mucus can drain out which is why you may not have a runny nose.
Antibiotics alone are not enough for some sinus problems. You are going to need to have a CT of the sinuses (not a ct of the brain) - a CT of the sinuses doesn't not require as much radiation and is optimized to evaluate the bony anatomy of your sinuses to see if there is any reason that things do not drain properly.
Facial pressure is a hallmark of sinusitis and sinus blockage.
Sinusitis is not always infectious, which is why antibiotics didn't help you.
If there is a structural difference in your sinuses which keeps them from draining properly (this can happen because of retained mucus plugging things up or bony narrowing over time) then the sinus ct would allow an ear nose and throat doctor to plan sinus surgery (not as scary as it sounds) because all they do is go in through the passageways and open up the ones that need widening a little bit.
This is far far more likely that than a tumor as you were worried about.
far more likely.
No they can develop
Not from birth
little polyps can grow over the openings
people go decades before having a problem
and your sinuses aren't even formed when you are born.
They expand as your skull grows
so even in your teens they aren't in their final configuration
Yes they are very rare in your age group. Sinus disease would be a few hundred times more likely
The skin would not be tender. It can hurt when you tap on your face, but not necessarily. The frontal pressure is the symptom that suggests this the most.
You can go see your primary care doctor and ask about getting a CT of the sinuses
Blood work doesn't rule out sinus disease or brain tumors
A brain tumor can be without symptoms for a very long time and also depending on location they can produce symptoms very early on. Again, could it be a brain tumor in a fraction of a percent yes, but the overwhelmingly likely cause is sinusitis, which may be due to a problem with your sinuses that needs to be evaluated with a CT scan.
Using a humidifier, saline nasal spray, antiinflammatory medication (over the counter like ibuprofen, paracetamol)
Warm showers - staying in there for a while so it humidifies the air is the same as using a humidifier
If your backup in your sinuses is due to swelling of the mucosal surfaces yes.
The tubes that drain your ears into the back of your throat can become closed off if you have swelling.
Taking an allergy medication over the counter type can help with those symptoms as well to minimize the swelling and allow things to open up and drain
as in metastatic? yes
primary are more rare
most common would be breast and lung cancer to metastasize to the brain
Yeah you have not to worry about brain tumors
it will be a sinus infection, non infectious plugging of the sinuses or a structural problem that would be fixed by minor surgery
Did I provide good service?
Glad to have helped calm you down a little - try to feel better and this well end up being fine.