Prickly heat type rash

I was diagnosed with breast cancer in July of this year. I have been suffering from a prickly heat type rash for several months, even before any cancer signs. It is not something I have suffered from in the past (apart from when I have been abroad). I was wondering in anyone else had this problem? Just curious as my breast care nurse doesn’t think its connected to the cancer but it just seems too coincidental to me xx