Inflammatory breast cancer concerns

I don't know why I have a bad feeling, I'm usually very stoical. But I started to get pain in my nipples a few weeks ago. Not the usual hormonal pain, really intense proper pain unlike anything I've had before.

Then the breast itching started just over a week ago. I scratched without thinking and it brought up a lot of petechiae. Since then the skin has been getting redder and scaley and is spreading over the breast. It looks a bit like angry eczema, but I'm 45 and never had this before. Haven't changed my detergent or soaps or anything else. There's a small unraised spot that looks a bit like a flat insect bite. 

The trouble is, it doesn't look that bad and if it were anywhere else on my body I'd ignore it and see if it got worse. I have had a dull pain in my armpit on the opposite side, but I've had that for about 2 years. 

I suppose I'd like to know if there's anything else I should be looking out for to put my mind at ease.