Pressure under left rib cage can have various causes, just like most other symptoms. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose pressure under left rib cage, we could:
MIDDLE-LEFT abdomen: Do you experience pressure or 'fullness' below your lower left rib which is painless or slightly tender? (Do not answer this question if there is significant pain.)
Possible responses:→ There is significant pain / don't know
→ Yes, slight pressure with no/slight pain
→ Yes, significant pressure with no/slight pain