I'm pregnant and I found two beat lumps in my right breast, due to the high level of estrogen from my baby, could that have caused it? Had biopsy on 1

Get follow-up. At the beginning of pregnancy, you should have a breast exam. If any lumps/bumps are found they can be imaged and less commonly, biopsied if there is concern. If the one that was biopsied was normal, I would recommend repeat imaging (likely ultrasound) in a couple of months of that lump and the other. Do your own exams also and if it is growing, be seen sooner. Usually these growths are benign.
Yes. Both benign and malignant tumors of the breast can be estrogen-sensitive, and grow during pregnancy. Complicating matters, the breast changes so much during pregnancy making identification of these lumps more confusing. Any new lump should prompt a visit to your ob; if concerning, you may be referred to a breast surgeon for evaluation+/-ultrasound+/-biopsy. As dr. Finke noted, most are benign.