I was told to burp for a full 20 mins and even if you don't hear a good burp they are still getting air out

if you can't get them to burp within 5 mins its not gunna happen. Try wellements organic gripe water, i had the same problem with my little one but not anymore.

maybe lay her across your knees and pat/rub her back! it worked on my boys

My love bug can a hard burped so when she was in the hospital one the nurses suggested rubbing her soft spot and then pat her on the back