I smoked for almost 50 years. I am just now getting to the point of not coughing anymore. I think I had/have years of crap to get out of my lungs. Don't worry about allergic reactions yet, you have to allow yourself to adjust to vaping. The best advice you've received is to drink lots of water. That should take care of the sore throat and even help with clearing out the phlegm.
Don't get discouraged everyone goes through an adjustment period.
Don't get discouraged everyone goes through an adjustment period.