A good start for learning clical piano?

Try this site below. As far as the sore fingers, that tells me you learning by force not finesse. You are developing bad technique which can result in limiting your playing as well as causing a host of painful and limiting strain on tendons and ligaments. You must find a nationally certified teacher and take lessons. These problems are not to be trifled with. There is a reason that teaching piano has evolved over several hundred years to become the most efficient and effective way of learning. There have been many who have ruined their hands. See the second site. Best wishes.