We stumbled upon this article from Scientific American and tried to see if your phone is indeed trying to kill you.
According to the article, recent studies spanning 10 years found that prolonged cellphone use produced a small risk of tumors forming in the hearts of rats. The test subjects were exposed to 9 hours of radiation daily for 2 years.
Now your phones do have some sort of protection and measurement of specific absorption rates. Additionally, they only release non-ionizing radiation which should not have enough energy to cause cancer.
However looking at some of the units in the market, the Nokia 8 and iPhone X were among those with the highest Specific Absorption Rating (SAR) which means they emit more radiation on use.