I spent most of yesterday at the doctor's and the outpatient section of the hospital. It turns out I have more fluid in my right lung (more than last time), which means more collapsed lung, which explains my breathlessness and pain in my chest and back.
Unfortunately, the fluid is compartmentalized into different pockets of my lung. The doctor originally wanted to drain a little over a liter, but he ended up getting just about a third of a liter. He wasn't sure what to do about the other sections, as the consistency of the fluid was unusual.
So I did get to go home last night (after a PET-CT scan which was already scheduled). I don't feel a whole lot better, but I see Dr. S. tomorrow, and maybe we'll learn more.