I would take her temp and have the vet on hold and banamine on hand (if that's safe for her at this point, I wouldn't know). It could be a mild colic due to her foaling (stress). She could just be foaling. It's hard to tell unless you're there in person. Does she seem colicky otherwise?? Does it look like she's trying to find a nest on the ground? Rolling isn't necessarily good if that seems to be her focus, I haven't seen a mare roll as part of foaling, except for a roll here and there to try to get comfortable.