Stomatch Buring ...?

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Lately i have been getting this wierd buring to my stomatch from the middle to the right side... (Diagnonal line)  ... I have been constipated also and my stomatch feels like its gonna burst, and i burp alot ... I fell gassy ... I havnt got my period in 2 months ... 
​Could someone help me with some advice or tell me thiere experience if they have felt this ..... Thnx