Worrying symptoms - rash on breast and pain in that area and my chest. Has anyone had anything similar and it's been benign?

Hi all,

I had a small rash develop on my left breast in the middle of September and I thought it was shingles so didn’t think anything of it. Then the following weeks, I’ve had such bad breast and chest pain. I had inflammation of the chest cartilage last year and assumed this had flared up again but two days ago my armpit has swollen up considerably, there’s a dark discolouration under my breast and its incredibly painful to touch. 

im unable to get a doctors appointment until Friday so I’m worrying myself sick. I’m just not sure what to do. I guess I’m asking if anyone has had something similar and it’s been something benign?