I had exactly the same problem and with the same percentage of vg. I now use 70% pg and 30% vg. Problem solved.
I realize most people have problems with high pg. In my case (and possibly yours) the situation is exactly the reverse. I speak from personal experience - not conventional wisdom.
Best choice, don't vape. Use other NRT's. If you can't do that for some reason:
Not all VG is created equally, it can come from many different sources. For example coconut, and some are allergic to coconuts. I've had VG that gave me hives before, switched it out, went away. Switched it back, came back. That was a long time ago.
You can try (with a rescue inhaler available) vaping some pure VG only. Or pure PG only. See if either alone trigger your issue. But do that in a safe place, heck, do it near a hospital emergency room if you feel it is necessary. Not breathing is deadly quickly.
Also eliminate flavoring completely and vape unflavored.
Also follow advice above, avoid huge clouds and try lowering nic. And also try some nic salts vs freebase nic and see if that makes a diff, but you may need to cut it or DIY your juice.
Don't over watt either. Too much heat produces "nasties" that could give you problems.
But if it's asthma...best solution is avoidance. Keep that inhaler handy along with a rescue inhaler if you continue vaping, even if you "solve this".

and best guesses. Good luck!