Nodules are very common and most will show no concern, however, if they are large and bothersome its' best to have them checked out to rule out any abnormalties.
Nodules. I understand that a nodule concern is if you have a large one. That impededes swallowing sometimes. I also understand that large ones may be or may become cancerous. A lot of nodules will also give you an unsightly, large neck. I had nodules that kept getting larger and spreading and caused hyper thyroid. Please discuss the ultrasound with your MD and try to get him or her to carefully explain what your nodules mean to your health.
Many of us have nodules on our thyroid, and they aren't a worry. The type and size of nodule will determine whether or not they are a concern.
Nodules have nothing to do with the thyroid medication you are taking and are not caused by taking it or by lack of it.
If you have a copy of the report, you might post it; there are some on the forum who are good at interpreting u/s results.