Wondering if Similac Alimentum is causing pain

My babes is almost 4 months his name is Rebel and he’s so sweet, but lately he’s been crying when being burped or even just after he’s ate a few ounces he currently on Similac Alimentum and I was wondering if anyone knows if this has happened to others. He’s not allergic to milk or anything but it’s a long story as to why he’s on this formula. Anyway he was doing fine but lately I get the feeling like he’s have trouble burping and like he’s in pain doesn’t last long but still I feel bad for him. I don’t want him in pain and don’t know if because he is getting older what the chances of it causing a stomach ache or acid reflux might be? Thanks