lapband surgery some times may cause gastro oesophagial reflux disorder [gerd]leadint oesophagitis,gastritis
that may cause pain .
Alcohol,coffee known to be gastric irritant and may cause pain .
Left lower abdominal pain
may be due to constipation
,commonly seen in post lapband surgery.
please discuss with your surgeon and find out and follow advice
For the time being avoid the things that are causing pain
Hope you be all right soon