My daughter's boyfriend vapes 0 nicotine. When he was using gas station cigalikes or the Evod setup we finally got for him (50/50 pg/vg on the Evod setup), he could take it or leave it. He was more of a "social vaper". For Christmas, my daughter said that he was fascinated with the clouds he saw patrons at a local vape shop blowing, and suggested that I look into a setup that I could afford that would let him blow clouds. I got him a Subox Mini kit. He is absolutely delighted, even with the eliquids that he has on hand at 50/50. He wound up with a headache and scratchy throat, even at 0 nicotine. My daughter and I both told him to drink more. No more problems. He has gone from being a "social vaper" to a person who is really enjoying his vape. Drink, drink, drink. It will help.
You may need to experiment a bit with your nicotine level and pg/vg ratio before you find the right level for you with the equipment you are using. At this point in time, vaping is very customizable, and you will find what works for you. Keep trying, drink more water or non-caffeine liquids, and play with your vape. Get smaller bottles of eliquid until you find the right combination of nicotine, vg, pg, and flavor for you, with the equipment that you are using.