well, you'll definitley need a new rocker arm on that right side..
Is the spark plug out when you're turning it by hand and it stops? If not, take it out and spin it by hand, if it's easier, then it could be a problem with that valve not opening causing excess compression....
if the spark plug is out, and it's still hitting... I would look for a brok valve, or valve seat popped out holding the valve down into the cylinder...
May be easier if you remove the head and inspect and look at everything.