Hello and welcome to MedHelp's forums. This is always an anxious time when you get a call back after a test. But remember, they are just requesting a further look to make sure all is well. Demographically, the odds would be against your having breast cancer at your age. But it is important to make sure and that is what they are doing. This is good medical practice. Many times they do additional imaging and let patients know all is well and other times they catch cancer at an easier stage to treat. Changes generally means they see something that warrants further evaluation. They are very common and most often do not mean cancer. That is directly from the American Cancer Society. https://www.cancer.gov/types/breast/breast-changes.
Dense breasts are something many women also have and this usually increases with age. This does pose a difficulties in mammogram imaging for getting a clear view and does put a woman at a higher risk of cancer. https://www.mayoclinic.org/tests-procedures/mammogram/in-depth/dense-breast-tissue/art-20123968.
Finally, yes, hormonal changes can create changes in our breasts. When is your follow up imaging?
It helps to stay busy and not catastrophize your thinking. Schedule as soon as possible to get it over with and have a friend or loved one go with you. Please let us know how it goes.