Gas issues

My little one is getting fairly close to a month old (in a few days) and he suddenly has, what is obviously, painful gas issues. He will cry, grunt, and turn bright red to let out some gas. I can't think of anything that is different. I'm still giving him his gas drops. He is having more wet diapers than before and still having plenty of bowel movements, but not at every feeding (like before this issue.) What do you think the culprit is?