When reading e-cigarette forums and browsing vendor websites, you'll likely see the term, throat hit, throat kick, or "throat stroke" frequently. As can be inferred from reading the expression in context, sore throat refers to the sensation that nicotine creates in the throat and in the lungs when inhaled. In fact, it is actually a slight irritation symptom, but smokers are accustomed to it and even appreciate it.
If you like that feeling, you may lose it with the purchase of a cartridge or liquid with a concentration of nicotine lower than the one you used before. If you try with a zero nicotine liquid, the experience may be very strange, as it feels almost as if you do not inhale anything at all.
It seems to me that almost any e-liquid with a nicotine concentration of 8 mg and above, can produce an excellent throbbing throat beat if that is the amount of nicotine to which we are accustomed. At 16 mg and above, the sore throat begins to enter the territory of the actual cigarette.
At 24 mg and above, the throat stroke becomes too intense for all except heavy smokers.