My doctor thinks I have a pinched nerve in my neck and wants to do an emg test? What does emg stand for, and how will this test help my doctor

Nerve & muscle test. Electromyography (EMG) is typically performed along with nerve conduction studies. When performed by a skilled physician (who also does a history & physical exam), these tests can identify nerve & muscle conditions at any point in the 'circuit' from part of the spinal cord, nerve root (exiting your spinal column), through the plexus, peripheral nerve, neuromuscular junction, and muscle.
See nerve damage. An EMG monitors electrical activity in the muscles to determine if there is disease in the muscle itself or in the nerves leading to it. By determining the pattern of muscles involved, the source of the problem can be localized (e.g. Pinched nerve in the arm compared to the neck), guiding proper treatment.
Electromyography. This test will help provide your physician isolate which nerve is irritated and to what degree the severity is. There are many nerves that can be "pinched" in the neck and treament options may vary depending on which nerve is involved.