Although electromyography is usually painless, the insertion of electrodes into muscles during the procedure sometimes causes slight pain or discomfort to patients, according to MedlinePlus. It is also normal for patients to feel sore and tender at the site of the tested muscle for a few days after the test.
An EMG procedure tests the health of muscles by stimulating them through their nerves and then checking for a response, as MedlinePlus explains. It also looks for any electrical activity. Muscle disorders and conditions that cause abnormal EMG results include carpal tunnel syndrome, Guillain-Barre syndrome, familial periodic paralysis, alcoholic neuropathy and sciatic nerve dysfunction.