You are not alone in this. I see hundreds of blogs describing the same symptoms after thyroid surgery. I asked my surgeon and my endochronologist about it being connected to the surgery and they both said they had never heard of it before. Maybe most people don't tell their doctors about it because they don't think it's related. Anyways, I went to an ENT doctor and he diagnosed it as Benign Paroxysmal Positional Vertigo, which has to do with calcified particles floating around in the inner ear.
While the surgeon does not think this has anything to do with the surgery, I disagree. During the surgery your head is held tilted back and taunt for the duration of the surgery. I believe this allows these particles to dislodge from where they normally sit and begin floating around in the inner ear, in effect, short circuiting the signals to the brain as they "ping" off the nerves located there. This is the how the ENT doctor explained it to me.
Anyways, he did a procedure on me that was effective and I have repeated the procedure at home. It is called the Epley procedure and can be done at home in five minutes. It gave me instant relief from the vertigo experienced when lying down. What it does is to relocate these particles back to where they came from. You can find the procedure online and it is simple to do. Try that and you will have instant relief. If it bothers you again, just repeat the procedure. It is important to know which ear is affected. You can figure that out by lying down with your head turned slightly first to the left and then to the right. Which side brings on the vertigo? That will be the affected side.
Good luck and I hope you get some relief.
There are multiple possible causes for vertigo, but yes, there can be a thyroid connection. Do you have any other symptoms that could be related to being hypothyroid? What thyroid med are you taking and what is the dosage? Please post your thyroid related test results and their reference ranges shown on the lab report so that members can assess the adequacy of your testing and treatment.