My husband feels blockage at the back sometimes while swallowing. also while lying down he feels gas blocking his back and is very discomfort able.

See a physician: I suggest that he be seen by a physician. IT is possible that he has a problem with his esophagus, which is the tube that goes from the mouth to the stomach.

Esophagus: It's possible that he has some esophageal dysfunction such as spasm, stricture,hiatal hernia, or GERD. I recommend a consultation with a gastroenterologist for diagnosis and treatment.