What Causes Bloating Under Ribs With Weak Diaphragm Post Gastric Bypass?

I had a gastric bypass years ago. Recently I have a tight bloated feeling under my left rib with boats of weakness in diaphragm . Ultrasound showed nothing and gasses in front of pancreas but no general masses. It feels pulled even in my back. When it gets weak. I feel breathless and a Ativan seems to help as does Bentyl . It almost feels muscular but getting worse and doesn t hurt. Just feels like a big lump inside. I have a cat w/o contrast next week . I had a chest x ray showed usual copd nothing new or changed. Thank you