What causes my chest muscles to hurt
Are you a girl or a guy? If you're a girl, it could be anything from being on your period, to just growing pains or something. On the other hand, you could have just been working out those muscles and they're sore now.
well, if you have been doing workouts that work the chest area, that would make your chest hurt, because it is trying to build muscle, and to do that, it will pull them a little bit, they will stop hurting soon
have you been working out maybe you stressed your muscles
maybe you are working more on chest, rest for while and soreness will be gone.