I was diagnosed with a muli-noduel goiter a few years back and i have also been on prevacid for a one month duration but that was after being diagnosed with an enlarged thyroid, for an acid problem i was suffering from. While I was on prevacid it really didn't cause me any difficulty with my throat.
Iam not on any thyroid medicine as regular blood tests show my thyroid still to be functioning normally. I do notice when I get upset or stressed out it does effect my throat...I will get a strange quivering sensation..and I feel a pressure in my throat like something is stuck in my throat and trying to cut off my airway. I go in for regular ultra-sounds on my throat so the doctor is able to see it these noduels have grown..but in the 3 years they have not grown one bit.
Talk to your doctor about your concerns, maybe you will need a blood test and an ulra-sound done on your throat.
take care and i wish you well :)