I have had a mammogram and an ultrasound done on these same lumps. The results came back as fibroadenomas. My doctor has given me a choice, and says the conservative way is to remove them, but they can just be watched. I am 34 years old. They are far more common than breast cancer, which is most often seen in older women.
Fibroadenomas never turn into cancer.
Nonetheless, almost all women are terrified by the idea of having a lump in their breast, and often want it removed, even when reassured that it cannot turn into cancer. So I can understand why your doctor has given you the choice of removing or not removing the tumors. Up until ten to 15 years ago, when breast biopsies were perfected, fibroadenomas were always removed, since there was no way to be absolutely sure that the mass was not malignant. Now, with needle biopsies, we are able to find out whether a mass is a fibroadenoma or a malignant tumor. We can choose not to remove the fibroadenomas, but simply to observe them with regular mammographies and breast self-exams.