Also, please post your actual T3, T4 and TSH results with reference ranges (ranges vary lab to lab and have to come from your own lab report). Do they say they are FREE T3 and FREE T4? "Normal" isn't always normal since the ranges are severely flawed and many of us feel hypo in the lower half of the ranges.
Have you had any other thyroid tests, like antibody tests (TPOab, TGab or TSI)?
How do you feel?
Are you taking thyroid meds?
The upper limit for thyroid volume for adult female is 18 cu cm, yours is 27.4 (second degree goiter)
The thyroid is enlarged and shows inflammatory process (this impression is known as a "Swiss cheese") The so called sub centimeter nodules are most likely spots with tussue damage due to the inflammation.