I use capsules & tinctures of CBD, I have tried to Vape but the next morning I am coughing up phlegm.

To me it sounds like you're doing larger hits when you vape and you maybe holding the medicine in, instead of blowing it right out.... Change things up a bit and do very small hits, blowing right out and I think your lungs will be much happier..... You too by the way... Good luck