Talk to Pediatrician on Picky Eating / Food Aversion

My son was breastfed til 1.5 yrs. He refused to take bottle. Not taking any milk. He is 2.3 yrs now and weighs only 11 kgs. 7 months ago he wa 12 kgs. He only eats a small range of food items. Most of the times eats fried chicken. Even feeding that to him has become a struggle. Specially in the mornings he will keep crying for hours but he won't eat. Feeding him is a struggle. Even if he is extremely hungry he won't take initiative to eat his food. I am so worried. Please help me what should I do. I am already giving him vydelin.