Stomach paining and cause is unclear.

I have been having stomach aches over the past month (on and off) which vary in pain. It makes me want to puke sometimes (sometimes I do) and it just hurts badly the other times. I have visited doctors and hospitals and had an ultrasound done with the doctors consent. The report I got said "There is evidence of multiple subcentimetric and borderline enlarged lymphnodes are seen in the precaval and para-aortic regions, largest measuring approx. 5mm in short axis dimension" I can't understand what this means and what impact it has on me. Please help me understand the problem and what steps I should take to getting back to normal. I was also asked by the doctor to take a test for TB. Please help. Thanks