thanks for writing to us.
first of all zanax is not a drug for high blood pressure
rather its an anti-anxiety
drug. moreover if your pain only comes after yelling and not after exercise, exertion, running etc, then chances of this being anginal pain are low.
for withdrawal of zanax you must consult a physician who is expert in de-addiction. and for your hypertension
consult a physician who will also assess the pain you have after yelling. i dont think pain has anything to do with withdrawal.
please post your further queries after consultations