What Causes Nausea Upon Yawning And Difficulty In Laughing?

Hello, i am male 25 years old.for the past six month i have body obiesity. Weight increased more.my face looks bloat.i cant able to laugh Normally.instead i laugh in difficult.my stomach gets full for a cup or lunch.i cant yarn too..when i try to yarn it gets to some kind of vomit sensation. I have cold too..The only problem is i smoke. I consulted many doctors.took abdominal scans too..but the prob still exist..please helo me sir!!!