If the Force is an energy field created by all living things, what did Yoda mean by
You must feel the Force around you; here, between you, me, the tree, the rock, everywhere, yes. Even between the land and the ship.
Trees, being living things, I could understand as having a connection to the Force, but rocks and starships? If midichlorians are the measure of one's connection to the Force, rocks, being non-biological, would not have midichlorians. For that matter, how can Force users manipulate inanimate objects that have no connection to the Force?