What would be causing me to feel pressure in my left temple? other symptoms include: headache, memory and visual disturbances, vomiting, and seizures.

Very concerned: Your symptoms sound very serious. You need an MRI of the brain. Please see a neurologist for a more focused diagnosis and treatment.

Headache and seizure: If these are new onset symptoms you should definitely go to the ed. Asap. You should also get a neurology evaluation promptly. This could be caused by various problems including tumors, vascular malformations, seizure disorder in general, even medication side effects.