Hi Bridie, As Tracey said, get your arm checked out. As for the burning guts with FEC, I did get heartburn/ reflux and went on Nexium and that helped that. I also had bad gut spasms, that usually started as a burning in my upper abdomen, & worked its way through my gut to be quite severe spasms when it got to my lower abdomen, & by the time the diarrhoea happened it was actually a relief. Nothing I tried really eloped, unfortunately. Don't know if that's what's happening for you. I hope not! It wasn't fun ??.
Take care, Lyn