There is a link between breast cancer and hyperthyroidism, and interestingly many breast surgeons are endocrine surgeons. I have Graves disease but it was not even mentioned to me when duagnised with breast cancer as my family history seemed most likely risk.
It may well just be an enlarged thyroid causing a goitre so yes important to get checked. I went on to have a CT but it was just an autoimmune and is under control with medication.
Thyroid conditions are extremely common and especially in women over 50. It's often included in routine blood screening because of this.