Why do guys always says idk?

Mostly because they tend to hold back there feelings or they are more than likely unsure of something or some even may be clueless. Men are different than woman in a lot of ways men tend to hold their feelings back more than a woman would for the fact its a man thing they want to show the toughness.

Boys Dont like to admit what theyre feeling,

if they say idk dont pressure them, just give them time....