The warning about not charging your phone under a pillow or on a bed is legitimate and based on real fire-safety concerns.
Here’s the simple reason: Phones and chargers naturally produce heat while charging. Soft surfaces like blankets, pillows, and mattresses trap that heat. Bedding materials are flammable. Damaged chargers, cheap cables, or faulty batteries increase the risk even more. That combination can occasionally lead to: overheating, battery swelling, melted chargers, smoke, or, in rare cases, fires. … Read more