Brief Answer:
Divarication of recti

Detailed Answer:
Hi.
Thanks for your quer, albeit short and specific.
Noted that you have a pronounced stomach bulge as explained when rising and have stomach gas too.
The commonest cause of the bulge I can think about in your age is divarication of recti. There is separation of both the strap muscles of abdomen near center called rectus abdominis and give belge from belly button to ribs when rising. This is not an actual hernia and there is no treatment other that strengthening the abdominal muscles.
Another cause can be an actual hernia.
If there are no symptoms associated with this bulge then nothing to worry as such.
If the bulge is associated with gaas then there may be concern, which I hope is not the case.
Gases can be due to many a reasons like GI flora disturbance, taking foods and beverages that can increase gas production, intestinal infection and so on.
You may please try probiotics, Activated Charcoal tablets, and avoid foods, beverages that cause more gases.
Get stool test done to see for intestinal infection and if present may need a treatment with proper antibiotic and Metronidazole. (prescription based)

I hope this answers your query, please feel free to ask for further relevant queries if you feel that there is a gap of communication. and give feedback too.

With Regards.
Dr T Chandrakant.
General Surgeon.

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