Hello,

Thanks for posting your query,

From your description, if the bulge is retractable or reducible then the chances of it being an umbilical hernia is high. As you described that it usually occurs when you lay on your stomach, meaning that your abdominal are highly tensed/contracted and if there is bridge on your abdominal wall, that will force intestines to bulge through the orifice hence you feeling it on your navel.
It will be best if you could pay a visit to a doctor who can take a closer look at it to determine exactly what it is.
Other possibilities are intraabdominal benign tumors.
Abdominal scan could help determine the nature of the bulge.

Hope this helps and wish you the best

Hi there! Does the swelling gets off automatically or by manipulation when you are lying straight on your back without any increase in your abdominal pressure ? If so it could be a reducible simple umbilical hernia, otherwise it is an irreducible umbilical hernia which needs urgent attention by a general / laparoscopic surgeon. At the same time, your doctor may possibly go for some more investigations as you have described the mass to be hard and increasing in size ( which perosnally I will not take on the lighter side) to exclude some more conditions which may need to be dealt by different kind of medical specialists. Take care.

Hi friend,
Welcome to Health Care Magic

Could only be a wild guess - unless examined.
The long duration / asymptomatic / intermittent visibility - favours hernia as first possibility
Get yourself examined - they too can get complicated...

Take care
Wishing speedy recovery
God bless
Good luck