Refusing to sleep

Please Help. Any advice or suggestions is greatful. Basically since my son has turned 1 he is refusing to go to sleep on his own. he used to be an amazing sleeper. always fell asleep on his own, would sleep through most nights. Now! omgoodness! He doesn't want to go to sleep at night at all n when he does he wakes up throughout the night n cries for hours. Nothing we r doing is helping. I will give him this he is just getting his second top front tooth coming through but he's been given some Nurofen plus some gel ... which usually always works ... so now I'm not sure if he is just in that much pain that what we normally do for his teeth isnt enough or if it's something else.. or if he is at some stage where they don't want to sleep... I dont know.. Any ideas?