What Causes Rashes With High BP And Fever?

Every month I break out with a Rash during the middle of the month, I am 69 yers old, at first it was under the left arm and with drainage which would happen for 8 months, then it quit under the arm and traveled under my left breast with drainage, once a month for 6 months that lasted for a good months, now it quit under the left breast and has traveled to the belly button with drainage, but every month I break out with this rash and it last unto 4 to 5 days! On top of that I have a lot of pain, my blood pressure jumps up where one time it landed me in the ER. I also get the shakes from this before the rash comes out. I have had the shingles shot and it has never been shingles according to my doctor, but he seems puzzled because I get the shakes and my BP goes up,,sometimes I get a fever from this but mostly a lot of pain.