Hi judekate. A goiter consists of extraneous thyroid tissue in a multi-nodule growth. When large, it is typically seen as a protrusion or swelling in your neck, and can cause pressure when swallowing.
Thyroiditis can result in a nodule or goiter, and it seems that your ultrasound showed evidence of such. "Heterogenocity" just means that there were different types of tissue visible on the image. Perhaps you have a nodule that is a different density than your thyroid gland, a little calcification (normal), etc.
The parathyroids are separate organs (positioned near, but not associated with thyroid function) that deal with the body's absorption of calcium. The most common irregularity in the parathyroids is a hyper condition that results in too much calcium in the body. Hypoparathyroidism (too little calcium) is much less common.
It sounds like your symptoms are related to thyroid rather than parathyroid issues, but the EndocrineWeb has a rather detailed section on both that may help you further.
<A HREF="http://www.endocrineweb.com" TARGET=_blank>http://www.endocrineweb.com</A>
Click on the link that says "Your Parathyroids" for more information.
