Suggest Treatment For Itchiness All Over The Body

I am a 44 year old obise male which for the past 3 weeks or so has itching all over my body with no visible signs. few days before i had a very severe back pain on the middle right side. when the back pain has passed pain in my heel begain. I have also a mild sore throat but iching is my main concern becouse it is making my life miserable. Can you please tell me what's the reoson for this itching?