What Causes Pain In Rib Cage And Rash On The Right Side Of Back?

Hi, I have had a rash on the right side of my back in two smallish areas for about four days, it is bumpy and itchy and red and the right side of my rib cage hurts, just below my arm from where my back meets my side all the way to my right breast, it is extremely painful to apply any pressure to it, but it does not hurt to breath. I have been mostly indoors and have done no strenuous activity.