How do I prevent burned chicken breasts when cooking on the stovetop?
I suspect the blackness comes from the spices you put on the chicken burning.

Try this technique I learnt from Jamie Oliver: Season your chicken as normal. Put the pan on a high heat until it's hot (not stupid-hot, just hot). Add olive oil and the chicken skin-side down. Cook for about 5 minutes.

Meanwhile, take a square of baking parchment or greaseproof paper big enough to cover the pan. Fold it in half until you have a 'folded fan' shape. Hold the point so it's roughly over the middle of the pan, and tear off any excess that goes over the side of the pan. Unfold and you should have a circle of paper. Scrunch it up, then run it under a cold tap and give it a shake.

Turn the chicken over, turn the heat to medium low, then place the wet paper (a 'cartouche') on to the chicken. Finally put a heavy pan lid (the lid from a casserole is ideal) on top. Cook for another 20 minutes.

The moisture in the cartouche helps keep the chicken moist and prevents it from burning. Cooking time will depend on the thickness of the breast, so do check it's cooked through before eating (cut it open and check it's not pink).