Several possible questions: first, what is your routine?
How long has this unusual crying been going on? Is it only during Activity time, or does she fuss/cry during feeding, naptime, etc.?
Does she seem to be in pain or ill? Has she got a fever? Is she waking in the night?
How is she eating? Are you sure she's satisfied? How is she sleeping? Could she be overtired?
Is she showing any signs of reflux? Does she cry more/less in certain positions? For example: while being held upright, while on tummy, while being rocked, while in stroller/pushchair?
Sorry to overwhelm, but this info will help people come up with ideas.