Key interaction not working

So I'm making an inventory system, and so far, it's collision based. I want to press 'E' to pick up the object, but adding a line enforcing that seems to make it fail.

Yes, I know I should probably be using rays for this, but while it's still rudimentary, I am using colliders until I know that everything else is working as intended.

this is the part of the script that is important, but if you need another part, just say so:

public void OnTriggerEnter(Collider other) { if (other.tag == "Item") { pickup = other.gameObject; AddItem(pickup); }

I've tried to add a && Input.GetKeyDown(KeyCode.E) to the if statement, but for some reason this makes it fail.