How is a pseudobursa diagnosed and can it cause persistent pain above belly button? (Photos)

I had a tummy tuck 18 years ago. Since June I have had persistent pain above my belly button. I have had ct scans and an endoscopy and was diagnosed with gerd and mild gastritis. The pain above my belly button is persistent and is bulging but no hernia was found. Would a pseudobursa show up on a CT scan? It's also very lumpy feeling and tender around the scar. I really need help. Thank you.