Oh, well I can tell you that Djarum Blacks tend to cause discomfort in the throat when you begin due to it's high clove content. Cloves tend to have that effect when burnt, I suggest you smoke more, and I'm sure this feeling of discomfort will disappear. It's totally normal, especially since they're Djarum Blacks. I went through a Kretek (Clove Cigarettes) phase and I would cough blood on a daily basis after awhile. Don't worry about it, keep smoking, it's just that you're still getting used to it.
Blame it on the cloves.