I have very sore and sensitive skin on my back. No rash or marks. Ear infection, sore throat, runny nose as well.?

Viral illness? You may also have an allergic reaction. The cause of your skin sensitivity is not clear, but may be the early onset of either an allergic reaction or Herpes zoster, the latter often presenting as pain or hypersensitivity before the onset of the eruption. Hope you are better soon.