The grunting sounds pretty normal - but the screaming might not be. If shes screaming & arching her back & acting like shes in pain - well she very well may be or at least be very uncomfortable. Some common things in your diet that might cause it are milk & tomatoes. Even if youre not drinking milk, it could be things in yur diet that contain milk that you might not realize contain milk. Remember whey, lecithin (sp?) etc are all milk products & contain the milk protein that can cause discomfort & gas in your baby. And the spit up. Tomatoes & other acidic foods can sometimes be the culprit as well.
You may ahve to experiment with your diet, there really are a variety of things it could be.
Some things you might try (other than cutting these foods out) is to take a digestive enzyme which will help prevent some of the proteins from passing into your milk. YOu can get it at a health food store. Also - gripe water - what a savior that can be.
Oh and btw - it takes 2 weeks for the protein in cows milk to completely get out of your system, so when you do cut it out - expect it to take up to 2 weeks before you see an improvement.
ANd of course - if youve tried all that - some babies are simply gassier & fussier than others. Their tummies are still adjusting to digesting period
Lala...