Heat is bad for the battery. Make sure you get air flow around the phone to keep if from getting hot.
On a side note, if you use Pandora. I had Pandora on mine. I seldom used it. Occasionally I would get a FC error even without running Pandora. So, I assume Pandora was running in the background. I deleted Pandora, and my battery life is definitely better, even though I didn't use Pandora.