I am very constipated. i feel the food i eat sitting in my stomach. very bloated and poop smells very burnt. what is the cause? what should be avoided

Constipation causes: Most common cause are dietary but you could have underlying physiologic abnormalities too. You should see a good doc who will get a good dietary history from you and must keep a detailed dietary history fort the next week or two. Then you will have to do a bowel prep as if you were going to get a colonoscopy. See a good gastroenterologist. Good luck!