Looking on the internet deeply has found these results:

how long have you had a stomachache is the most popular phrase on the web.

how long do you have a stomachache 10 results on the web	how long have you had a stomachache 11 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	(be cold). How long have you had a stomachache? 2 (rash). How long have you had that rash? 3 (feel dizzy). How long have you felt/been feeling dizzy? 4

how long do you have a stomachache

10 results on the web

how long have you had a stomachache

11 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.