Whenever i stand up i get light headed, but like feels there's pressure in my brain. it goes away some days i wont have that feeling. brain cancer?

You are describing: what is called orthostatic hypotension: a feeling of weakness/dizziness when moving from a laying to an upright position: benign, unless you have some underlying heart condition.

Agree with Dr M: If there is some intracranial mass the pressure would get greater when laying down so sounds like orthoststic hypotension.That is usually caused by anemia,dehydration,medications,etc.Sometimes this is heart related but at 22 less likely but not impossible I would go see a primary doc and drink plenty of water