I would have bilateral ultrasound . My cancer never showed up on mammo or original ultrasound. I felt lump myself after mammo and ultrasound. I had mri and my cancer was discovered after ultrasound pinpointed cancer that I felt lump. Do the bilateral ultrasound. I am doing bilateral ultrasound and mri in April. My mammo did not show the cancer. The mri did. And the ulta sound did but I had to point to the cancer I felt. Ultra sound no radiation so do it bilaterally. My cancer was cobweb type and did not show up on mammo. If I did not feel it, and insist on another mammo and ultra sound it would have kept growing. Because my cancer was small and my oncotype was 16. Not in lymphnodes or margins. No radiation or hormone blocker. Chance of cancer coming back 8%. 4% if I do blocker. 90% chance not coming back. I am going to do a bilateral ultrasound in April and do another mri. Make sure ultra sound tech goes over every 1/8 th inch of both breasts and underarms. Then have an mri. As I said my mammo did not show my cancer. The ultra sound did not show my cancer. I luckily felt the lump myself. It was close to the skin at 12:30 6cm from nipple. 11mm. You have to be your own advocate. It is good your doctor is checking your other breast too. Good luck