See regular Dr 1st
Most stooling issues can be handled by your regular doctor. A dietary history, stooling history & review of issues can often point the way to a simple DX and plan for improvement.
If the initial workup or rx is not helpful, additional eval thru a GI specialist may be necessary. In my local, the gi's won't see kids <18, so a 50-100 mile trip to a pedi GI is an extra burden.