Nap time and co-sleeping?

My son is 11 weeks old. We co-sleep/bed share with him. I am having the most difficult time getting him to take a nap. During the day I can get him to nap in his swing but in order to do this I have to rock the swing harder than it goes until he falls asleep. I would like to get him to be able to fall asleep by either rocking him myself in the glider or by just laying him down. I have only been able to rock him myself a couple of times, I usually end up putting him in the swing after 45 minutes of rocking and a very agitated baby. He is exclusively fed. He will not fall asleep on the unless he is extremely tired. Any tips on how to get this boy to fall asleep easier?