Thanks for writing to us
The pain at the bottom of the rib cage
on the left side could be due to a renal infection
or a stone if the pain does not seem to be muscular in nature. This can be ruled out after getting an ultrasound
If the pain is aggravated with deep breathing or coughing then a rib injury
or a muscular sprain is likely.
I do hope that you have found something helpful and I will be glad to answer any further query.