About 5 days ago I suddenly noticed that my nipple on my left breast was tender to touch and had some pain. It started all of a sudden and the color is normal, nipple not inverted, and not oozing anything. I only have pain when my nipple touches something. My breasts are large and the nipple constantly gets in the way of things, such as the table , the countertop, and etc. What could this be. Could this be the start fo breast cancer?