Cut pork neck into bite-sized pieces.
Slice onion, green onion, and carrot into appropriate sizes.
Make the marinade with soy sauce, gochujang, sugar, minced garlic, pepper, and sesame oil.
Add the marinade to the pork neck and vegetables, and mix well.
Heat cooking oil in a pan and stir-fry the marinated pork neck and vegetables.
Stir-fry over medium heat until the meat is fully cooked.