Pressure in the left side of my head for nearly 2 weeks. doesn't cause any pain but it does cause dizziness and unequal pupil size. what is it?

See a neurologist: I suggest you seek a neurologic opinion, without a thorough history and neurological examination and evaluation especially when dealing the head and cranial nerves, it is difficult to commit to a specific diagnosis with limited information.

Insufficient data: It is impossible to say exactly what is going on ,age, blood pressure, other symptoms or complicating comorbid conditions, medications,,state of your "nerves" all matter. give details