Help!! Found under nipple

Looking for some advise 2 days ago I found this little thing right under my nipple at first it felt like grissle (only way to describe it) when I squeeze it there is pain and moves. It was really hard but since going in the shower it’s become softer and more whiter where as it would only go white when really stretching the skin. Anyone know what it may be or experienced anything like it? Any advise would be appreciated. Tia

(Waiting for a call back from the doctor)