d damage which has been done already to lungs by tuberculosis bacteria like making small cavities here n dere  is causing this trouble.these damaged area take time to heal..though there is no or tuberculosis bacteria..since u hv completed the course. avoid triggers which cause these spells since the pressure during such cough spell cn burst any artery of ur lung which might cm out with ur cough so be aware of dat. mean while to stop this take syp Grilinctus 2tbs thrice a day if dere is fever u might need antibiotics get a hemogram done and consult with reports.