I just discovered a large, tender lump in the very lower-inner quadrant of my breast extending below my breast towards my sternum.. Approximately 1.5 - 2 inches in size. The skin around this lump is red. Prior to discovering this lump I saw my PCP who ordered my 1st screening mammogram which I haven't had yet. Should I go ahead and have the screening mammogram or should I see my physician first? Will a mammogram show a lump this low in my breast?