I don’t know if this is helpful but I can relate to the crawling feeling, which in my case progressed to fasciculations (twitching you can see under the skin). These fasciculations can be triggered by movement. It may be the same, I don’t know.
I’ve never got to the bottom of these, except for the fact that I used to get hundreds of the fasciculations every day, every second some part of my body would be fluttering or twitching. Yet, when I was put into a Philadelphia cervical collar 24/7 (in 2007) these substantially reduced in frequency, duration and intensity. So, some of it could be to do with transmission through the vagus nerve (which transmits messages from each part of the body, back to the brain, notifying it of what’s going on).
However, I do believe there is something additional not right, such as electrolyte, mineral and vitamin malbalance or deficiency. Off the top of my head I remember both Potassium and Magnesium mentioned in this aspect but there’s more that I can’t remember, or don’t know of. One thing is for certain, that I have been advised this year of certain deficiencies (see the end of my diagnoses list below)
Head & Neck Injury (June 2002); Mild Concussion; Post Concussion Syndrome; Postural Orthostatic Tachycardia Syndrome (POTS); Peripheral Vestibular Dysfunction; Mild Radiculopathy & Small Fibre Neuropathy (right leg & foot resp.); Partially Empty Sella Oct 2002 (worse by Oct 2004); Whiplash Associated Disorder (WAD); 3mm Cerebellar Ectopia (Chiari 0); Cranio-cervical Instability (CCI) with Posterior Gliding (PG) & Cranial Settling (CS); Brain Compression; Retroflexed Odontoid; Stretched/Elongated Brainstem; Ehlers Danlos (EDS) type 111; Osteoarthritis; Arrhythmias (Bigeminy and Trigeminy). . . and now Mitochondrial Dysfunction, Mineral (Mg,Mn,Cu,Zn,Selenium), CoEnzymeQ10 & Vitamin (C,D,B3,B12) Deficiencies!