Preheat oven to 350 F
In a large bowl mix together yogurt, sugar, oil, eggs, vanilla and milk.
In a second smaller bowl sift together flour, cocoa, baking powder, baking soda, salt and chocolate chunks and chips.
Add the flour mixture to the yogurt mixture and whisk until combined. Do not over mix.
Spoon into prepared muffin tins.
Place in oven and bake for 15 - 20 minutes or until a toothpick inserted comes out clean.
Remove from oven and let sit in pan on a baking rack for about 10 minutes. Remove muffins to rack and let continue to cool.
Store in a sealed container.