You are most likely using too high heat for too long time.

High heat with short exposure time makes a nice crispy external layer, but trying to cook something through on high heat will result in the outside being burned/overcooked whit the inside being anywhere from done to in extreme cases raw. The heat simply didn't have time to penetrate into food before the edges become too hot.
To cook food through, use lower heat with enough time for the heat to get into the food. It is still very possible to overcook it, even burn it, but that requires much more longer cooking time giving larger margin for error. It also makes it possible to cook things through, especially thicker pieces, before their edges end up overcooked or even burnt.
The sous vide method is an extreme case where heat is lowest possible and cooking time is very long. It gives very wide margin for error, results in impossbily evenly cooked food, burning it is literally impossible.

Experiment with bringing the heat down. If feeling unsure about meat being undercooked, use food thermometer, online resources will provide you with safe temperatures. With experience you will find your most comfortable stove setting.

Low heat, long time - cooking
high heat, shirt time - searing/sauteing

high heat, long time - charcoal