I've had bilateral mastectomy 2 months ago due to IDC in left breast,1.5 cm,grade 1, stage 1, N0M0. I am 47. No chemo yet, waiting for a second opinion. Three Sentinel nodes were removed during surgery on my left side-negative. I developed a seroma on this side in my armpit which was partially drained twice( both times 20cc) under ultrasound guidence,and came back again. Moreover, I have a lump about 4 cm in length under the lt insicion. I feel pressure, burning and pain in this area.