i had the same problem when i started vaping.....
coughed really hard on almost every puff i took....
fruity/smoother flavors and lower nic levels seemed to help a little but still coughed from them...
however after a few days this went away completely...didnt have to change juices or anything, now i vape 36mg carts with no problem....from what ive read a lot of people do cough a bit for the first few days...i know i coughed quite a bit for the first couple days i vaped, but then by the end of the first week i wasnt coughing at all...
i know it can be rough, but hang in there, hopefully it will get better, especially if you play around with different types/nic levels in the juice im sure you can find something that suits you....
did you cough at all when you smoked analogs?