I Have A Rush Under My Left Breast And Between

I have a rush under my left breast and between my breast on the top of my stomach. I have some discomfort inside around the rib area, thought it was due to too tight of a bra. I just had surgery 9 weeks ago and pericarditis 2 weeks ago. I am 69 years old . Could this be shingles? My doctor did a test and said I did not have this virus in my body because. I had them do the test because I don't think I had chicken packs as a kid.