I keep coughing when i smoke!?

when i first started smoking marijuana, like anyone else i would cough when i took big hits. its been a year or so and now all of a sudden i start coughing when i take big rips and my tbroat hurts (sometimes i cant even talk!) but anyways, i got use to taking such big hits and now whenever i do i start dying! (not litterally, juss coughing a lot! and i can be coughing for a while) hah, has this happened to you? anyone know whats goin on? :p oh and i also start cough when i take deep breaths or just breathe, this all started happening at the same time thoo.