I'm late to the party, but Janice I absolutely would (and do ) use blends in a quilt. And if you machine quilt there is no better backing then double knit for a quilt! imo
Terriamn reflux is a definite possibility, or hiatal hernia. Take an otc proton pump inhibitor (like Prilosec) you will know pretty quickly if it is reflux, I call it my magic little purple pill.