Welcome in H.c.m.
I have gone through your query regarding small hole in neck since birth, it swells time to time and does not hurt but lakes yellowish fluid.
Considering all aspects of your complaints it appears that you are having bronchial fistula. this is a congenital defect. As far as treatment is concern that is only surgical correction. Before surgery one investigation called as sinogram is must to identify the entire tract and than excise the entire sinus
I hope your query is explained.