Q: Is it normal for iPhone 4 to heat up a lot during use?

Hello Vmurphy96,

When troubleshooting temperature, please refer to the following article:

iPhone, iPad, and iPod touch (4th generation): Keeping device within acceptable operating temperatures

http://support.apple.com/kb/HT2101

When using the device or charging the battery, it is normal for it to get warm. The exterior of the device functions as a cooling surface that transfers heat from inside the device to the cooler air outside.

By all means, if you believe the temperature is a concern, you can isolate the issue by restoring your iPhone as new:

iTunes: Restoring iOS software

http://support.apple.com/kb/HT1414

Thanks,

Matt M.