Hi thanks for your question
Your hypothyroid and taking synthyroid for you hypothyroidism
Enlargement of thyroid gland producing swelling in the neck occurs in hypothyroidism and is normal.
Thyroid tissue gets hypertrophied in response to low thyroid hormone level in the body.
I your thyroid swelling f it is not too big (goiter
).it will regress itself in due course of time
Hope i answered your question.