I was having issues with VG just flat-out suffocating me, using as little as 33% VG, because I have asthma. However I've recently determined that vaping high-PG plays absolute hell with my hydration and electrolytes, so I've had to go to a high VG juice. I thin it with [distilled] water, and so far, it's not suffocating me, not giving me that "hairball" feeling in my throat or chest.
Someone suggested to me to start diluting the VG with water at 5% dilution, but that doesn't make enough difference to make it any different for me; I actually dilute a high-VG juice with 25% water -- 3 parts high-VG ejuice, 1 part water. Since you're using 100% VG, that might be a little too much dilution, but I'd suggest starting at no less than 10% dilution, see if that helps, and move up in 5% increments if you need it thinner still.
I believe it's the thick viscosity that causes my own problems; YMMV.
Andria
PS: what he said above about dehydration is no joke, but just "drink more water" may not cut it; even sports drinks may not keep you properly hydrated. I'm using coconut water daily to fix my own dehydration and electrolyte imbalance, and now that it seems fixed, to keep it fixed! But mainly it seems to be the potassium my body needed to correct the problems, and that's a problem-area for a lot of folks, who may be taking all kinds of medications that interfere with the sodium/potassium balance.