1. Combine cake mix, cherry pie filling, and three eggs. Mix until well blended.
2. Bake in well greased and floured 9 x 13 pan. Bake at 350 degrees F (175 degrees C) for 35 to 40 minutes.
3. To Make Frosting: Combine sugar, butter or margarine, and milk. Bring to a boil, stirring constantly, and cook 1 minute.
4. Remove from heat.
5. Stir in chocolate pieces until melted and smooth.
6. Frost when cake is cool.