Talk to Pediatrician on Colic & Stomach Ache

AoA! My baby girl is almost 3 months old and weighs 4.1 kg. She has colic problem for which doctor prescribed her colic drops (colirest drops, colrid drops & boost syrup). From few days she put her hands on her stomach and cry excessively. Sometimes she passes gas without crying and sometimes she put hands on stomach and growling sound comes from her tummy. Moreover when I tried to burp her, its seems gas is gathered at the end of stomach and in the left side of her tummy. Plz tell me why she is having stomach ache? She is on motherfeed and one feeder of NeoLac 1 at night time. I want to ask the reason of stomach ache and is there any test to check whether she is well or not. Her paediatrician said she is okay and just have colic. But I'm not satisfied with his answer.