rash on breast.

Anya🕉 • 🐾24 ; mother of two, soon three💓 girl mom
So I had a rash on both breasts about a month ago. But nowI have another only on one breast, it's slightly worrying me because it's only on one and I think that can be a sign of cancer, anyways it's only on the right side, there is nothing I do to this breast but not the other. Lol
Also the nipple (not areola) is itchy too, it gets unbearable at times! 
Please help?