Extremely ITCHY breasts!

Hi. I want to ask you ladies,what can be some causes/reasons behind my itchy breasts??? I have been using the same soap for months,so I'm sure it is not that.I lotion and moisturize my breasts often,and they do not sweat often. The sections that it itches most, are under the breasts,and mid section of the breasts. Ladies give me some advice on what could be the cause of this!