A very common question that is often seen from a skeptical seeker is this one. "If we're all one, how come if I stick myself with a pin, my neighbor doesn't feel it."
The seeker asking this question is still stuck in the "I am the body" assumption. He believes that the Oneness is somehow a oneness of bodies, or bodyness. He has not yet discerned that the One that he is, is not physical, is not a thing.
All bodies and things appear in the One, but each is a singular focal point in the field of Awareness. Awareness is aware of each and every object in the field. Yet, any apparent body will feel it's own aches and pains, its own mental suffering. Why? Because each body unit has usurped awareness as its own. A fatal assumption! An nnocent mistake, but one that leads down every path to ignorance.
That which permits body units to apparently exist is aware of everything. It is the perceiving "No Thing" allowing everything. The One is aware when the seeker is poked, and when the neighbor is poked.
Once a seeker realizes that he is Awareness itself, and not the body, the question based on oneness of bodies subsides.