I beat eye of cthulhu and slime king, now I'm spending eternity looking for platinum ore underground. It was ass at first, then got fun, now it's back to being ass. When does it get fun again?
Get some bombs, go to the corruption/crimson (whatever your world has), and break those orbs over there. To get to the orbs bomb the rocks and smash them with your hammer from there, it's smooth sailing.