painful gas pain at night only

For some time now my husband has been waking me with a pain that scares the **** out of him. He states that he can lay down and get ready to go to sleep and about 15 minutes later he has this bloating feeling in his stomach that moves up to his chest and it is so painful he can't even lay his hands on his chest.He also states that is it feels like there is hot water being poured over his head. He states that it also feels like his insides are moving around and twisting and turning from all of this pain. This all is very weird for me and don't understand it. I have a difficult husband that won't go to the doctor, but I am really trying to encourage him to do so. The pain is really bad and difficult to understand. He will get up and take a Zantac and about fifiteen go away. He has to take Morphine and Flexiril for chronic back pian and has chronic constipation due to the medication. What in the world is going on? What should we try???