TB skin tests should not be given to people that have a documented positive test in the past. However if you do not bring these results with you to the testing, they will do the test again. Get documentation of your positive tests and carry it with you when you are screened for TB. Even if you were treated for latent TB in the past, the skin test will continue to be positive and repeat testing is not indicated. Repeat chest x-rays in these people is also NOT recommended, unless there is some reason to think they have active TB, i.e. if they have developed symptoms of TB. When chest x-rays are done it is usually a day or two to get the results back.
I would advise you to contact your local health department and speak with the person who handles TB. They will want to know if you were foreign-born, if you ever got BCG vaccine, if you have any symptoms, of TB, when you had the positive tests and how large the reactions were, and if you have ever been treated for TB. They can advise you from there.