[Q] my razr xt910 always get warm/hot after little usage. problem about radio?

Hi, i'm from indonesia. i got motorola razr xt910, from my friend. and the Android version is 4.0.4 out of the box.
here's the detail in about phone:

system version: 673.94.328.XT910.AsiaRetail.en.03
model number: XT910
Android version: 4.0.4
firmware configuration version: GAS_ASIA_USASPDRICSIRD_P021
Baseband version: U_04.11.01P

and my razr always hot, warm enough in the back side and the touchscreen also get hot. I just use the phone to use socmed apps (instagram, path, bbm, whatsapp) and brows the web, but not gaming. at all.
i just use 5-10 min, and get hot.

I tried use CM11, slimkat, mokee, and any kexec rom. it's hot too.
i tried custom stock rom JB 4.1.2, and it runs great, but getting hot too.
my question is:
1. is there any relation my problem with the stock rom? so, which version should I try to flash via RSD?


if it can be solved by flash another firmware, let me know. if not, tomorrow i'll try to go to service centre. it's still in warranty

thx a lot guys