Phone gets hot and draining battery fast when LTE is on
My note 5 is starting to get hot and draining battery fast about 2 days ago. That is when I am on LTE network. This never happened before as Note 5 is one of the coolest phone I ever owned even using constant gaming. Now when I am on LTE, even if my screen is off, the phone gets very warm after 3-5 minutes and battery is training as much as 1-3% per minute. When I set my network mode to 3G or 2G only, this doesn't happen. Once I turn it back to LTE auto, and it is on LTE, it sucks my battery and the phone's temperature is up that it is extremely uncomfortable to hold.
I also tried cooling it in from of an AC, yeah it stops the heating outside but still drains the battery fast. WIFI works fine too.
I think my LTE radio is broken or something. I can still use internet properly even at LTE though so it is still functioning well. What might be the cause of my problem?