I had discomfort just under the ribs on the left side of my abdomen when I first started prednisone. It felt like a pressure as if something was enlarged. It wasn't constant but I felt it at points nearly every day for over a month. I had that feeling once before when I injured my spleen. I mentioned it to both my rheumatologist and hematologist oncologist but it didn't present as anything discernable. I'm not sure what it was but it went away by the time I started tapering down on prednisone.