It all depends
Is it all day or does it happen the same time of the day. It could be a couple of different things go on. It could be gas and colic. We give our daughter the gas drops with every bottle and that seems to help. It could be the formula too. With Bailey we've had to try several different formulas and now she's on Nutramegin (sp?). If you think it's really bad talk to your doctor. I kept a notebook with different colors for everything that way when I brought up a concern I could easily look back at the book. She ended up sending us to specialist. Bailey is defiantly doing better now. Honestly thought the best piece of advice is follow your gut and heart. If you think something is wrong keep track of what's going and take him in. The worst they can tell you is that it's normal.