iOS 11.2.6 overheating and draining more battery

Hello everyone. I bought my Iphone 7 32GB a month ago, and since I upload to iOS 11.2.6 (two weeks ago) start to noted that the phone gets hot without a heavy use. I can be using safari and it gets hot, using whatsapp too. Whit almost every app happens the same. For example, today I watch the Infinity War trailer on youtube app and the iphone get a LOT hotter, at the point that I have to stop using it cause that temperature worries me. This temperatures are anormal for a new device..

Almost, the battery starts to drain with more facitily than before. In one hour of use I lost a 10% or more of capacity ALWAYS. It's worse than before the actualization. But when I lock the phone and leave it whitout use, comebacks to the normals temperatures and the battery don't drain. So is not working bad at all.

I have restored the Iphone to fabric state two times. One with the phone settings and the other with iTunes in my computer. And the problem persist. I have chatted with apple support and the battery is okay, so... supouse the problem is iOS 11.2.6, cause before it this things didn't happend to my iphone.

I'm the only one with this problem? Someone knows a tip or something to fix it?