What you are experiencing can be caused be several things:
Vapor is different from smoke. It took your body time to get used to smoke in your throat and lungs, the same is true with warm vapor. As time progresses and your body adjusts, this will become less of a problem to you.
As pointed out before me, your draw technique may need to be adjusted to vaping. Some cigarette smokers inhaled directly into their lungs. Since the nicotine in vapor is absorbed more in the mouth, nose, and throat and not in the lungs, pull the vapor into the mouth and hold it there temporarily to allow it to cool a little. Then allow some into your lungs, or exhale through your nose and mouth.
Relating to the flavor, years of smoking have damaged your taste buds. They will heal, but it will take some time. Flavors will taste off initially. What you may like now, you may grow to dislike, and visa versa. The Pg and Vg in e-liquid both draw water from our cells, so drinking plenty of water is very important to replace what is lost. Dry mouth also contributes to one's ability to taste.
I personally found some of the clearomizers to give a harsh vape, especially top-coil, top-wicked ones. You may find a cooler and smoother vape using one of the bottom-coil, bottom-wicked clearomizers such as the Kanger Evod or Kanger Protank.
Using a higher resistance, or ohm, delivery device will also cool the vapor. Low resistance or low ohms cause warmer vapor, and may be experienced as harsh.
Having a variable voltage battery such as an eGo Spinner or Twist allows for further fine-tuning of the vape temperature, and can also be used to adjust to different flavors. If your delivery device allows for different types of drip tips (mouth pieces), finding a especially long one can allow the vapor to cool via the longer distance the vapor has to travel from the coil to your mouth.