What Causes Itching In The Cleavage?

For months now, my cleavage has been itching on and off. I have been using the same soaps and perfumes for years now. So it cant be allergic reaction or can it? Im pretty well off with my immune system. Im 26. Also I noticed a week ago these small clear like fluid blisters forming on the sides of my breasts, next to large red bumps. No open sores or anything. It was just weird. The itching is unbearable, and its freaking me out. I also found out that breast cancer and heart failure, (problems) run in my biological side of the family, in only the female side. I found this yesterday evening. Which didnt put any ease in my thought process. Is this a form of cancer to have itchy breasts like this? Especially when its been a year with this horrible itchiness?