What kind of viruses cause lower abdominal/ around belly button pain (only) n takes 5-7 days of healing?

Numerous. there are many viruses that can cause such symptoms. However, such a presentation is not limited to viruses but could be bacterial or parasites. In fact many bacterial causes of intestinal infection such as campylobacter (the most common) self resolve in such a time frame. When talking viral infections, they generally are self limiting. the key thing to remember: many viral and nonviral causes.
A lot. Any can set off the immune system. Pain is not only caused by inflammation of the intestinal lining; It is also caused by mesenteric lymphadenitis. Lymph nodes throughout your belly become pit stops for lymphocytes - warrior cells - to collect info, get activated, and get ready to coordinate an attack. Your timeline is tricky, because you have to consider incubation periods as well.
Gastroenteritis. Several types of viruses can cause gastroenteritis which usually runs its course in several days. However if you have repeated episodes of abdominal discomfort and tenderness with bowel symptoms, repeated viral infections would be unlikely and you should see your physician for evaluation of other conditions like colitis,diverticulitis,adhesions,hernia,etc.
Not that common. to cause pain. Diarrhea, nausea, vomiting would be echo viruses, adenoviruses both are very common and norwalk/rotovirus pretty common. Apparently astroviruses have been a new agent in the last 15 yrs. http://viralzone.expasy.org/all_by_species/678.html Pain.. none directly but adenovirus can cause lymph nodes and irritation that might do it OR. diverticulitis, hernia, pulled muscle non-viral.