the change in size can be related to the blood veslles/ lymph ducts compression in the neck due to thyroid enlargement.
When I developed a goiter it was very noticeable. I had the neck of a football lineman. I was only 5'2 and 88lbs. There was no denying my goiter.
I did end up with hyper/graves. I also went undiagnosed for 6 months because they attributed all my symptoms to post partum depression. It was not until I developed a goiter that they jumped into action.
They say it is heriditary, but out of 15 sibilings, I am the only one who had graves. No one else on either side of the family has graves.
Before i had a Total Thyroidectomy, i also noticed that my goiter was sometimes unnoticeable and very noticeable during other times. Lymph nodes are normal and can become swollen when there is an infection.