Usually you would hear it as singular: 'Ease the inconvenience' "Having a game app on your iPhone can ease the inconvenience of waiting for a delayed flight." "The new road will ease the inconvenience to travelers from the slow traffic."

The word "collocation" is correct, but it is an academic word. The word "expression" is very appropriate. However, phrase is suitable and it will do. In English, you can say this, and it should be understood. It is not an expression. A good thing about English is that you can say almost anything and it is understood, but that does not mean it is an expression. We say "To ease your worries" a lot, but that is a different topic.