my toddler used to eat all the time now he's being a picky eater??

EVER since my son had this cold couple weeks ago he have not been eating like he used to now he's eating like a bird ugh! it's very irritating and I looked on Google other moms having same problems and that doctor's saying it's normal I have try everything cut down snacks, juice, and small portions and even try feed it to him he Cry's it's very annoying trying my best for real like he eats when he wants too. !! have any moms dealing with this. 🤦🤦🤷🙅🤔😑😒 PS : I believe his running nose and sneezing coming back. he had problems previous with mucus issues since birth !