Thank you for posting your question here, I will try to answer it to the best of my abilities.
A lump under your ribs can be a sign of something serious. Lumps in the body can be swollen lymph nodes
, a tumor
or a cyst
I also recommend you ask your GP to run your blood and check for any abnormalities, ask him to run a biochemical analysis as well.
If possible ask your hospital to run an angiography
on you, to check for aneurysms.
And by the way, I am really sorry about the way you were treated at the hospital, I am surprised they think you have a blockage when you seem to be going to the toilet normally.
I hope my advice helps.