It comes in short (1 - 5 second) bursts in the center of my left leg right under my butt, usually more frequent after working out or trying to stretch the leg. I've had an mri done of my lumbar and pelvis looking for a pinched nerve, and a ncs and emg, but nothing has cropped up. I've had treatment on the leg in the past for sciatica based off of tingling down the leg, which comes back if I've had a relatively physical day. Laying down makes it better. Any ideas would be helpful.