Have had a rash on upper back for a week with a constant sore throat, rash is starting to spread. Itchy but not burning, getting concerned?

Itchy rash. Rashes can be tricky. Are you on any medications you might be reacting to? You could consider a paid consultation so we could see the rash and offer more personalized help. Stay cool. Itchy rashes itch more in the heat.
Symtoms. With all your symptoms, best to get an evaluation to determine if you have a possible throat infection, and what is causing the rash. Best wishes to you.