My skin is sore to touch from the center of my belly around the right side to my back. it began suddenly as a sensitive spot in my back. what is that?

Sore skin: The issue you describe may be consistent with shingles. This rash tends to begin as pain in a dermatome. A dermatome is a region of the skin that is innervated by a sensory nerve, and generally wraps around the trunk, arm, leg, etc. The pain may be severe, and a papular rash may develop. Anyone with chicken pox as a child may develop shingles later in life, particularly in times of stress