I have had left lateral upper thigh numbness x 3 wks. now deep aching inside. numbness is slowly traveling down leg.? emg help diagnose

Yes: You are describing nerve pain. An EMG consists of testing the health and speed of your nerve function, followed by electrode insertion to the muscle for a specialist to access the nerve and muscle connections. This will answer the question of what nerve is causing your pain. Treatment and symptom control begin with a real diagnosis. Good luck.