i have fat pads over my collar bone.. it that
part of weight gain...
Fat pad over the collar bone is not specific to particular medical illness. it is most likely part of body weight. It is not uncommon to see fat pads around the neck and collar area with overweight / obesity.
However if you are over weight / obese, it is important to check for thyroid dysfunction as well as diabetes. In case you haven't had those test yet, worthwhile to get it done.
Hope this helps. Let me know if you need clarifications.