What Causes Blockage In The Ears?

My right ear has been plugged for a few weeks I went to the ear nose throat doctor last week and he unplugged it but it came back a couple days later I can hear my blood swooshing through my ear, my blood pressure is low and seems good also every time I swallow I can hear it in that ear and my nose has been draining in my throat its not mucus ie or anything but I think that's what's causing my ear to block any ideas