Q: ipohone 5 gets hot

That means it's working.

iOS devices: Keeping device within acceptable operating temperatures

If it's too hot to comfortably hold something is wrong. Restore it according to the instructions in this document.

If it is still uncomfortably hot have it evaluated by Apple.

I had the same problem and apple offered to replace it with a refurbished iphone 5S. Why should a customer settle for a refurbished one when it is less than 3 months old.