How would you prepare the following marinated chicken without a grill? I tried pan searing my chicken after marinating for 24 hrs but completely blackened the exterior without cooking the inside much. Would the oven retain the marinade flavor, should I invest in a griddle, or just change recipes?
I'd say the difference between frying or even using a griddle pan is that compared to a grill [US] barbecue [UK] that the latter generates more heat all round the food as it's cooking, as opposed to mainly the portion touching the surface of the pan.
With that in mind, some possible solutions…
Fry then oven - would give you the surface texture plus enough time to cook the inside. [Oven then fry might work too, though the surface would then be more difficult to fry evenly].
Butterfly the chicken before marinating, or even just slice in half - half the thickness, quicker to cook to the centre, with double the crispy surface & more marinade on it. Stronger flavour & a change in the proportion of textures, but you may like it that way.
Broil [US] grill [UK] with a more controlled temperature. You could achieve a similar, though not identical result compared to the default grill/barbecue method. You can decrease cooking time slightly by using metal skewers through the centre, like a kebab.
You could try one of these pans or something similar (I just grabbed a google image for the bottom more than anything). Before I had a griddle I used my stove with something like that and my food generally turned out not as you described, and I use a lot of marinades and sauces in my cooking.
Also check what temperature your setting your oven to, if are using a pan for something like this turn down the heat and cook it slower.