why do solid thyroid nodules form
Several potential causes.
I have gone through your query and here is my opinion.
Sometimes,thyroid cells can grow out of control and form a lump on your thyroid.
Solid nodules are solid lumps that form within your thyroid and usualy do not produce symptoms.
Iodine deficiency, which is very uncommon all around the world, is also known to cause thyroid nodules.
Hashimoto's thyroiditis,aan autoimune disease which is the most common cause of hypothyroidism , is associated with an increased risk of thyroid nodules.
At the other side the genetic predisposition is very important for developing thyroid nodules.
Hope i have clarified your doubts.