Why isnt my high blood pressure under control even when I take medication?

I am currently under 2 medications (Ambeon & Benicar HD) and my HBP is still giving me headaches on the back of my neck, I know by experance that this where HBP headaches happend. What could be going on?
Update: correction on meds: it is Aceon and NOT Ambien sorry
19 answers 19