I had a cervical epideral for left arm and neck pain and the following week an emg same aera would that make the test normal?

Unlikely: The esi is to help decrease inflammation and pain, but would not reverse EMG nerve abnormalities in a week, and might take additional 4-6 wks if it acted totally in an effective fashion.

Cervical EMG: Emg/nerve conduction studies help to determine the "pain generator", level when positive but when negative it could be that nerve isnt irritated enough to reveal a pos result. Scientists refer to this concept as the sensitivity and specificity of a test. Could an injection turn a nerve that would have been positive to negative? Yes, but could also have been negative before injection.