When I sleep, according to my husband, I can breathe in normally through my nose, but then pause and am unable to breathe out through my nose. I eventually push out a breath through my mouth. I also wake up with sore abdominal muscles. I have had a sleep study which showed no sleep apnea. I don't feel stuffed up, what could be the problem. I am also incredibly tired during the days despite 7-8 hrs of sleep. Thanks!