Hi Doctor, I Have Had Itchy Skin On My Torso

Hi doctor,
I have had itchy skin on my torso back and for over a week now. My skin feels bumpy and i have had red sore spots particularly between my breasts on my breast bone, i am not large breasted by the way, and small red spots here and there that go dry and when i scratch they bleed a little. I am guessing its from keeping my body warm by continually wearing thermals as its been cold. Can you help