Answer: Well, from what my research is saying. cell phones emit low levels of non-ionizing radiation when in use. It can also referred to as radio frequency (RF) energy. And as stated by the National Cancer Institute, "there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans. So, it has not been proven weather or not you could get a tumor or cancer from the energy waves.
Some information about a radio wave is that we can have an energy of around 4 x 10-10 eV.
Okay so, I do think people should limit their cell phone use for other reasons. For one, Phones can be overly addicting, I do speak from experience. Phones can also take up way to much of your time is you're just scrolling around on them.
Explanation: So at least that's what I would say. Hope this helped! :)