What Causes Rashes On Back Of Scapula And Armpit?

HI, I have a rash on my back by my right scapula and a smaller rash by my right arm pit, they are both hurting and tingling, what can this be? I am basically in good health. I was however, diagnosed with colon cancer ayear and 10 months ago. I am done with all treatment and currently free of cancer. I am 5ft 4" tall and weigh 123lbs, i am a dancer and very active.