** Extremely Dense Breasts - Worried **

Hello... I'm hoping to get a little more insight or advice on my situation. I'm a 35 year old and found out I was pregnant with my first in March of this year and then unfortunately miscarried in May. Since the pregnancy, my breasts were already getting bigger and very sore. I did start to notice a slight change in my right armpit area, there were no nodules or pea sized bumps just a raised area that was tender. Recently after the miscarriage I noticed it was still there, my breasts started to go down in size a little and no more swelling. I decided to go to my GYN and she did agree that there was some swelling in the axilla area and suggested I go get a mammogram and ultrasound. This being my first time doing a mammogram I was a little nervous. My doctor suggested that I get the ultrasound first and mention to the technician to have the doctor look at it first before doing a mammogram in case it wasn't needed. The doctor didn't see anything with my breast or armpit (lymphs) on ultrasound but to be sure recommended I go ahead and do the mammo while I was there and because of my age. They did the mammo and after the nurse came out and said everything was fine. I said that's great, but also asked then why does my armpit area still feel tender, they couldn't give me an answer.

Fast forward to a week later, I got my results in the mail and pictures to view online. I read the letter and it was very confusing. It said " no cancer, but extremely dense breasts. BI-RADS Category 2: Benign Findings. Screen in one year. Dense Fibrograndular tissue is noted in all qaundrants of the right breast, no new suspicious solid mass or suspicious area of shadowing."

My concern is that after reading the letter and reading forums online it seems very dense breast tissue is common however it doesn't help in finding cancer. I did view my pictures online and my breast tissue is pretty much all white, everything. You can hardly see anything except white.

I talked with my GYN again on the results and she honestly thinks that I should wait and see if it goes down or if I notice anymore changes. She said with the pregnancy and miscarriage it takes awhile for the body to get back to normal and the hormones to level. I voiced my concerns on cancer or inflammatory cancer and she said she still honestly thinks to not worry at this moment in time. But I am worrying because I keep thinking in my head what if the hormones went out of wack and started something up in my breast tissue. I'm really confused on what to do. It's been going on three months now that I've had a tender breast and underarm. Recently I noticed it was tender in my right breast at around 6 0'clock, this morning I woke up and the tenderness and the aches moved to the side near the armpit. Armpit isn't as tender unless I press on it. Not sure why I feel more aches in this breast before I wake up, then when I get up and I start moving around I don't feel it anymore unless I actually press on it. I'm a worry wart and am really hoping it's just hormones or maybe extra breast tissue etc, but I can't help not thinking it's more.

I'm just not sure what to do, should I insist on an MRI or wait? A breast biopsy or wait?

Thanks!