I have a tender beast what is it?

One tender breast?: I trust you are up-to-date on your mammogram; if not, this is a good time to schedule. Breast cancer doesn't usually show up as tenderness. Rather, there's a lump or thickening in the breast, sometimes a pulling sensation, etc. A breast cyst (typically, a benign fluid-filled lump) can be tender. Mastitis (breast infection) brings pain and fever. Check with your doctor - and update your mammogram.