To answer your original question,
Tren sweats are caused by different things in different people. Some get them while others do not. Unfortunately, there have never been any human tests done and no data is available so we're just guessing and going off of experience. Seeing that tren has the ability to burn body fat like thermogenics, I attribute this to part of the problem, also as with any thermogenic, carbs fuel them as does protein to a lesser degree. Tren is also claimed to operate on the central nervous system and this could be a factor to this as well as insomnia. Of course these are all speculation as the hard data isn't available.
The cough is due to impurities in the gear / pellets. Some powders and pellets are more pure than others. Others claim that while injecting it, hitting a vein will cause the "cough". Again, just speculation but some swear by it.