Every phone I have ever had has gotten warm after a few minutes use. Normal for ALL phones.
HTH
You probably have an 1000h battery. It's is now almost useless. Here is the thing, the battery warms up and it begins to swell. You'll notice that the battery life is a joke. You may have read reviews that the phone have horrible battery life, but in actually the phone comes with a bad battery.
Spin test. Remove the battery and place it on a clean, flat surface. Spin it and if it spins pretty well, it's a swollen. Verizon will tell some bull about that its your phone, but luckily they have something to sell you. Don't bother, go to LG and purchase it their or at amazon. DON'T GIVE THEM ANYMORE OF YOUR MONEY. I purchase an extended battery and I was suprised. It's been 24hrs and still no need to recharge.