hm.....so much here that is 'unknown': maybe you just like to please others. and there might be oodles of reasons for that, not all of them positive and altruistic. i know that sometimes i am too uncomfortable to say no, though i really don't want to do the thing asked or offered. something i work on.
you didn't ask if it is an addiction, but if it might be a manifestation of addiction, which i think is a slightly different question.
off the cuff here, i'm thinking it might be a manifestation more of not having found a balance between worklife and the rest of your life....which lack of unfound balance in itself might be a manifestation of something akin to addiction. (having trouble with "addiction", as i don't see people as being in addiction when they have stopped for a while already. "alcoholism" comes closer, for me, but is another can of worms best not added here)
how do you experience it feeling-wise?