Emg showed increased insertional activity in one muscle. i have chronic muscle cramping during activity all over my body. electrolyte, blood and genetic tests are all normal. no muscle weakness or atrophy. can this still be a neuro/muscular disorder?

Based upon your post, see no reason to suspect a neuromuscular disorder at this point. The EMG findings are inconsequential. The cramping may respond to magnesium supplements, but you may do even better by a physical therapy and exercise program. A virtual consult here at HT could review your testing and provide further directions (www.connect@healthtap.com).