Go see your doctor. Get everything checked out. Make sure you have everything set up including a good "rescue" plan that may or may not include a nebulizer. It's not unheard of with asthma or COPD for high VG juices to cause problems. The reasons for that... I have no idea.
I will say, I wouldn't (personally) as someone with an asthmatic son continue to vape and play around with different juices without your doctor's BLESSING and a REALLY GOOD RESCUE PLAN. Asthma can be deadly, as can COPD if it has progressed far enough.
IF your doc says okay to vaping and gives you a rescue plan, I would start over with a small, MTL tank, and use a much higher PG level (it's one of the ingredients that makes up vaping).
IF you get your doctor's blessing and a GOOD rescue plan, then come back, ask us a LOT of questions about a good setup, a good juice (I'm sorry, but what you have now won't get refunded because you happen to have asthma, it doesn't work that way) and THEN PROCEED once you are INFORMED TOTALLY about vaping and liquids that may play well with your health condition.
I don't want to do that now, because I'm not .prepared to give you specific advice UNTIL you see your doctor. I don't want to you to be an ACCIDENTAL casualty of getting the wrong ADVICE without an adequate RESCUE plan in place. Sorry, but breathing is quite essential to life. It may well be possible that a few simple adjustments can make vaping easier and more enjoyable.... AFTER you see your doctor for an adequate rescue plan.
I will say, many folks with COPD and/or asthma do fine vaping, and often better than when they were smoking: WITH their doctor's blessing and support and using the RIGHT equipment and the right type of e-liquid.
Welcome.
Anna