Hi,my cat had 5 kittens there 4weeks old now but I have notice them sneezing and 2 of them have waterey eyes and a bit sore is this life fretning?

Better safe than sorry, you should get them in to the vet for a check over.
It may very well be an upper respiratory infection, if so they need antibiotics.
If they are stuffy and stopped up it may interfere with nursing and eating and this could be dangerous for a tiny kitten.