For years, when running competively, I would look at my calves when sitting down and notice what looked like worms traveling around under the skin. Never figured out what it was. I was well hydrated but would have liked to have had massage therapy on a regular basis. For a 5'10' 145# distance guy with 15 1/2" calves and chronic calf problems the shoes & medical help available today would've extended my running career.
Try regular massage therapy first and then, maybe, anti-seizure meds. The muscle neurons are firing uncontrollably for some reason.