I had a ultrasound guided FNA 10 days ago and it was a piece of cake, not nearly as bad as having a tooth filled or pulled. I had a lidocaine injection before the procedure began and in 15 or 20 minutes the whole thing was over. I felt only a slight pressure. About 3 hours later I felt a little pain and took a couple of tylenol and it away and never came back; only a little soreness the next day and after that nothing at all. Don't be afraid it will be okay.
I've had a total of three fna's...and i had local anesthesia for one because this particular surgeon gives it to all of his patients....what you will feel is: a needle ***** and then pressure 'several" times when he/she is drawing out the biopsy. The procedure takes no more than 5mins..if that.
As far as the Thyroidectomy...i am scheduled to have one next month...however, many people on this site can share their experiences with you.
I didn't get any valium with my FNA. It doesn't really "hurt" so much as it feels bizarre. I got stuck a total of 5 times and only the last one felt kind of icky. Like nails on a chalkboard. But, my neck was very sore for about 2 weeks afterwards. Felt bruised. Thyroidectomy is not nearly as bad as you are probably making it in your head. I wasn't in any pain after the surgery and I didn't take any meds. I was up and around the next day. It does hurt to cough or sneeze for a few weeks but other than that, you'll be amazed that you were ever worried.
I didn't have too much pain, and no valium...good luck. Thyroidectomy is pretty easy as surgery goes...felt fine after a day, was up walking two miles three days after. No real pain, no complications, and I had the surgery twice.