you need an indica. heres some of my favorites for pain and sleep. they all have great yield and potency. they are sure to get you stoned and unmotivated in a hurry
-northern lights(classic)
-ICE (really gets you stoned)(cannabis cup winner)
-warlock
-Black Berry kush(awesome)
-anything like skunk or the afghany land race type strains, northern lights is 50% from afghanistan(home of the indica lol)