The reflux disease is known as "GERD" in short
here are the symptoms associated with it
5) sour reflux coming up to mouth.
a) IRRITABLE BOWEL SYNDROME
and (b) INFLAMMATORY BOWEL DISEASES are different set of disease with some what similar symptoms.
i)BUT With the IBS - the first one in list it just occurs in stressed out condition with bowel irritation with any thing, and its not associated with any thing that can give lump in the ribs,
ii)In inflammatory bowel diseases like crohn's disease / ulcerative colitis
may lead to a cancer in a very long and that can be some what associated with.
But have an IRRITABLE BOWEL SYNDROME AND ITS NOT ASSOCIATED WITH LUMP IN RIBS,
I still having more concern ask your physician to get the lump checked by Ultrasound
and biopsy later on.