My thyroid testings were always normal. A cyst was found and aspirated three times (returning larger and quicker each time) with the lab results coming back as "normal body fluids". My papillary thyroid cancer was diagnosed when they removed the cyst. 6 weeks later I was back in for surgery and had a total thyroidectomy and several lymph nodes removed. Make sure that all the test possible are done and if nothing shows just monitor it. Small thyroid cysts or nodules are a common occurrence. They can be harmless if they are not affecting the function of the thyroid gland.
your TSH may be normal, but ask your doctor to check your TPO antibodies. You can have a normal TSH and still have thyroid autoimmune disease. The antibodies in your blood cause the goiter due to your own body attacking your thyroid. I was told for 7 years I had normal thyroid blood tests until one doctor did the TPO test and I was diagnosed with Hashimotos Thyroiditis. I also had a goiter twice the size of my thyroid.
I have normal blood work but have a small tumor on my thyroid found during a CT scan trying to eliminate possible causes for my symptoms. A followup scan 3 months later showed no change and I'm supposed to have annother scan 12 months after the last one just to make sure.