What are her poos like when she does do them? That would be the best indicator of whether or not she is constipated ... constipated feeling can often be accompanied by diarrhea - if there is a hard poo that is not coming out then only the soft poo can get passed so if her poos are always soft or always little hard pellets (or a combination of both), I would say that she is constipated.

If there is nothing in her nappy when you check it, but she is really straining, there is a good chance that she is constipated as well.

Having said that, lots of babies grunt and groan when they poo. They can be quite entertaining to watch.

And I think it is very cute if she is growling and screaming for attention. I love that they know they are the centre of the universe at that age. They act shocked that mummy would actually want to spend time doing anything other than doting on them ... it's a gorgeous age!