Believable thought labels about exercising.

Hi! I’m having trouble with thought labels about exercising, I identified my thoughts and emotions about that and I know exercise is good for my health and loose weight but I think I can’t really believe it. My thoughts are that exercise cause pain and discomfort, can’t breath, and “why would I begin again if I’m gonna drop it in a few days or weeks”. I know that thoughts are the wrong part here but it’s difficult for me to find something I can really believe right now. Thank u >n<