I had a nerve conduction test done for my spine on my legs. 2 days later i developed a cramp in one of my calves that won't go away. could this be a side effect?

Did you experience a severe muscle cramp in that calf during the EMG? I've only heard of very mild muscle spasms occurring during an EMG but not enough to cause persistent muscle pain. With severe muscle cramps tiny muscle tears can occur& cause more prolonged discomfort.

An EMG/ NCS is very benign and although may be uncomfortable at time of study, does NOT cause any lasting complications of any sort, other than local bruising rarely where needle inserted. The calf cramping is likely related to the spine issues and NOT the EMG study. Contact your doctor and get this addressed.