For the past two years i have been getting severe throbbing pain to the left side of my head/brain. it comes and goes but sometimes i'm in agony.

See a doctor: Please see a doctor about this, your symptoms are not normal. This sounds like migraine, but there are other conditions with similar symptoms.

Behavioral medicine: Presuming that you have been thoroughly examined by your doc, you might consider some behavioral interventions. Your BP might also be elevated due to the pain. Herbert benson, md, a cardiologist has a great little technique called the relaxation response that might be helpful in relaxing the vessels in your head.