Phone Getting hot when on cellular


I’m a new member to Verizon, and I’m a former subscriber to AT&T. Everything has been going great, but I’ve been noticing my phone get unusually hot when I’m connected to cellular. On AT&T, I don’t recall my phone getting hot while on cellular. I tested this by turning off cellular with Wifi on then turning off WiFi and turning cellular back on. My phone would get hot within a few seconds. Is this because AT&T is on a GSM network and Verizon is not? Is something wrong with my phone?