pain from Foley catheter while in labor with epidural?!


my sister in law is in the hospital right now and has been since last night for being induced at 41 weeks. she is only 2cm dialated and they broke her water and have now gave her the epidural and obviously put a Foley catheter in... but the catheter is causing her so much pain she is literally screaming... why would this be? she had them remove it and put a new one in just in case someone put it in wrong but it is still very very painful all the way to her butt she said she can feel it. even through the epidural. could the catheter be too big??? just trying to find out some answers or advice I can give her before I get up to the hospital in about an hour?!?! I've had two kids both with epidurals and have never had this before!