I m an active runner and have been experiencing bad pain in both my calves right where all the mucscles come together. The pain usually comes on after I have run a few miles, then starts to feel like a burn, then graduates to a severe burning like pain at the center of the calf muscle belly. I have to stop running and the pain subsides a bit, but usually lasts for 2-3 days after my run. It s not a cramp , but more of a burning pain. The pain alternates from one leg to the other. Running seems to bring it on the most, but it has been agitated from other excercises, like swimming, as well. Thouhts on what this might be?