I was told I will leave the hospital with a surgical drain. Can anyone tell me what is its purpose? Is it painful?

In laymans terms this is what I was told...The purpose of the drain is to allow excess fluids/ little blood out of the surgical area, my surgeon also uses it for his second leak test. I would not describe it as painful but it was a bit uncomfortable. I was glad to have it out. I had a 3 day hospital stay and the drain was removed end of day two. I had a second leak test day 2 with the a blue dye substance and once they where assured none of the blue dye had leaked from my stomach my drain came out. Because the drain hole does not get a stitch (it is allowed to heal from the inside out) it was the most tender of my incisions.

I tend to have a low pain tolerance, but this did not cause me pain...just discomfort