Very oily skin no matter how much washed. Painful itchy skin. Rash on back face neck scalp. Skin hurts. New soap. Reaction maybe?

You may. It may be severe seborrheic dermatitis. See dermatologist to discuss treatment options.
Rash. This can't be diagnosed with the information that is available. A history, physical examination & other studies may be needed to determine cause/causes. Once accurately assessed a treatment plan can be developed.