I know this is an old thread but I've had this problem for years. The SAME exact feeling and reaction that you had. I could not figure it out at first but I noticed it happened almost 5 to 10 minutes after I smoked. It didn't happen all the time and it didn't matter what weed I smoked or what food I ate before, or if I didn't eat at all. It mostly happened if I smoked too much and my stomach and esophagus would seem like they tightened up. My chest would start to hurt and I would get shortness of breath. Then I would have this huge burp start to build up and all of a sudden it would SLOWLY start squeezing out of my throat. Then this would repeat over and over for sometimes 2 hours or more. I tried eating cookies and gummies and the same thing would happen when the treats were too strong. So I started to pay close attention to what really caused this to happen. It's not smoke cause the same thing happens with treats or vape. I believe it may be the amount you smoke which then causes an anxiety reaction which makes the gas even worse. I believe something in the stomach and lower esophagus tightens/closes up and is not able to quickly release the huge amount of gas that's forming in your belly. So it builds up and gives a sore feeling to your chest until you burp it out. If the burp seems to slowly "squeeze" out of your stomach then our symptoms match up pretty well. So, in conclusion. I think strong weed, or too much THC, plus creating an anxiety situation, tightens stomach and/or esophageal muscles causing the gas to build up without a clear escape route. This in turn makes the anxiety worse and the gas worse. But there is a quick cure if you have access to a good doctor who is understanding of your situation. The thing that works for me is called Alprazolam. Just a .25 mg pill and my gas and anxiety subside within 10 to 15 minutes. Now .25 is the lowest does you can take but I might take 2 or 3 of these a month so they work easy on me. Others might need a slightly higher dose. Remember, I am no doctor, but I do know the symptoms well. This also may need to be studied closer because it seems to be more of this going around than first realized. It may be that some doctors haven't been able to put this together yet because many people go to the hospital for this and wont admit weed use. It's been 5 years, let's see if anyone else has these symptoms now.