Is this a chest infection or just a common flu thing... ?? I'm not sure..?

You need to take something to help loosen the stuff in your chest. You can try mucinex or Robitussin cough syrup. Increase your fluid intake while you take these so it can work faster. Also increase your vitamin c intake (try emergen-c) since it helps loosen phlegm as well. If your in cooler climate make sure your chest is covered up while out till you feel better. If you have a vitamin shoppe near you there is a homeopathic remedy called causti which will loosen your chest up in a couple of days. Feel better.