Preheat the oven to 425 degrees. Coat a muffin tin with cooking spray.
In a large bowl, mix together the flour, baking powder, baking soda, and salt until well combined.
In a separate bowl, whisk together the sugar, melted butter, and egg until well combined. Add the sour cream, milk, and vanilla extract and whisk until creamy and smooth.
Gradually add the liquid mixture to the flour mixture until just combined. Add most of the strawberries and chocolate chips then mix until combined.
Fill the muffin tin evenly with the muffin batter. Add any remaining chocolate chips and strawberries to the top of each muffin.
Place into the oven and bake for 5 minutes. Reduce the heat to 350 degrees and continue to cook for 13-15 minutes, or until a tester inserted in the center comes out clean. Remove from the oven and cool in the pan for a few minutes before putting them on a wire rack to finish cooling.
Make the chocolate drizzle by placing the dark chocolate chips in a glass bowl along with 1/8 teaspoon of coconut oil. Put the dish into the microwave for 30 seconds. Remove and stir then place back into the microwave for 20 seconds. Remove and stir then place back into the microwave for 10 seconds. Remove and stir until completely melted. If needed, continue cooking for 10-second increments. Be careful not to overcook the chocolate!
Spoon the chocolate into a zip lock bag and snip a very small hole in the corner with scissors.
Drizzle melted chocolate over each muffin. Serve and enjoy.