Hello rae11180
I was told a year and a half ago that thyroid issues can be linked to breast cancer by the Cleveland Clinic. It would appear that this association is getting more common if you keep reading posts about it on different sites and on this one. Ask your oncologist and ENT and you may be surprised by what they tell you.
best wishes
Dear rae11180, Thyroid nodules may have nothing to do with your history of breast cancer, however it is likely they will evaluate it further to better characterize this nodule.