Are both sentences natural?
(I mean something happened to all of us in our lives)

We've all been through this. or We've all been through these.

Question

Are both sentences natural?
(I mean something happened to all of us in our lives)

We've all been through this. or  We've all been through these.

Answer

"We've all went through this" and "We've all went through these" are both correct, it's just that one is in the single form, whereas the other is in the plural form.