Kitchen tiles are burning hot in a specific area?

I have just noticed today that in a area of my kitchen the tiles are burning hot to the touch. So, something underneath the tiles are causing them to get so hot that you can't even touch one of them. One tile is def. the hottest to narrow down the spot. The surrounding tiles are warm and getting warmer as the day has progressed. We have lived here for a little over a year and there used to be vents in the flooring but they have been cemented in. There is a vent in the kitchen on the floor but cemented in and we cover it with a rug. Our house is built on a slab of concrete and there is no crawl space underneath. I have no idea as to what could make them that hot. And no its not from the sun, nor an old vent, so please any ideas or advice on what to do or who to call would be more than appreciated. Thanks for reading! Amanda