After my thyroidectomy the nurse came round with toast for us! That was the last thing I expected to be eating, but actually it was fine. I have found you get offered no fruit or vegetables in hospital, so I now always bring a bag of salad and soft fruit like plums. I was very tired after, so chewing is more an issue than sore throat.
I had my thyroid out in 2 halves, and both times I came in early morning, had my op late morning, it took 4-ish hours. Then stayed over night. The first time they were keen to get rid of me by late morning. But the second time I ended up slipping through the cracks, they obviously didn't need my bed for anyone else, an I was begging you get discharged, but didn't get out till 8pm. I've seen about 10 other people on wards having the same op and out of those 1 was kept for a few days. She was an elderly woman with other conditions who couldn't keep food down.
I had nothing I would call pain, but some discomfort. Things like coughing could be a little painful. I took paracetamol for a long time afterwards as it also reduced some of my hypothyroid symptoms of dizziness, etc.
I agree with others that you should ask some stiff questions about whether you really need this operation. You will likely have a slightly lower quality of life than others for your whole life after having it. And some people like me are very unlucky, I've been disabled for 4 years, lost my job, hobbies, have struggled to wash and dress myself. So it is not something to be taken lightly.