I would like to welcome you to HealingWell. That rattle in your chest could be bronchitis or a cold that is getting worse. I don't necessarily know that it means that you have asthma. Have you had shortness of breath or any other asthma type symptoms? You most definitely need to see your doctor right away because a rattle in your chest is something that needs to be checked. Are you a smoker?
Please let us know what you find out and please keep posting.