My heart was beating fast for first 2 months, it still does time to time when i exercise or do something wrong. I wasnt able to even look at pc or tv then, now i can watch tv or play video games all day long.

Heart rate can get only high again if i drink or smoke which i aint gonna do yet.
I assume your son isnt doing none of em and wont so he should get better with time. My stomach has hurted time to time nothing special, USG showed nothing. I vomited just twice, and ice tea, tea not food.