there are a few things that can cause harshness
sometimes it is just the flavor that you are using
but usually it's the pg level...higher pg = more throat hit, higher vg = less throat hit
it could also be the nic that you are using, are you using freebase and the juice you used to buy was nic salt?
or it could be that you are mixing a higher nic level then what you are used to (this usually also causes a peppery taste if using freebase nic)
me personally I do not like a throat hit at all so I buy nic salts in 100% vg and then mix at max vg, I never add any pg to my mixes because keep in mind that the flavorings add a bit of pg themselves (unless you specifically buy flavorings in vg)
I would up the vg level the next time that you make it
and you might want to after making the juice and shaking the crap out of it, let it sit for a day or so with the cap off...maybe the flavoring contains alcohol...
if you still find it harsh you can add a drop or two of vg to your atty
if using a tank and you find that the juice is too thick and isn't wicking right, you could add a drop or two of distilled water to the tank to help thin the juice out to wick better...I use rda's so don't really have that issue.