Is this normal?

He just won’t burp or will after AGES! I often just give up because he doesn’t but the problem is he usually drinks 3 ounces every 2-3 hours however ever since he stopped burping so easily he only drinks 2 ounces and stops and keeps leaving 1 ounce. If he does burp he is able to finish

How can I make him burp again? I rub his back upright, try sitting on lap and rubbing back etc and he just doesn’t and gets agitated and pushes back !!

Help