Well from what you are describing, it sounds like that you may have a couple of conditions. The first one which comes to mind is that you could have developed a problem with the stomach itself. Increased production of acid in teh stomach can lead to bloating, burning pain in the region, belching as well as nausea and vomiting. This can occur in conditions like gastritis or even an ulcer. the diagnosis is made clinically and also with an endoscopy and then treated with stronger anti acid drugs like esomeprazole or dexilant.
Now the tenderness has me worried as that you usually indicates a serious inflammatory disorder which is occuring inside the abdomen. This could be due to intestinal obstruction which is a condition in which there is blockage in the intestines and even though you passed some stool, there may be some residual blockage left inside. This can cause abdominal distension, tenderness and needs to be evaluated immediately with the help of a simple xray of the abdomen and if needed an ultrasound.
Another cause of this could be pancreatitis which is a condition in which teh pancreas are inflammed and that would lead to pain in the upper part of teh abdomen as well as tenderness. this would need a CT scan to be diagnosed and then treated with Iv medications including antibiotics and fluids. Similarly inflammation of teh gallbladder which is known as cholecystitis would also cause pain in the upper abdomen and would need an ultrasound to be diagnosed.
Now because of the tenderness, i would STRONGLY advise you to visit an urgent care center or the ER and get a clinical examination done ASAP. If needed they can even do an ultrasound, if you didnt have the tenderness i could advise you to wait but in the presence of tenderness (pain on pressing down), it is best to go to the ER.
Do you have any more questions?
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