Hi A.,
I know you posted this a couple weeks ago and have had lots of great feedback, but I just wanted to share my ideas with you.
I also have a 1 yr old (15 months now)and for the past couple months has gotten finicky with sleep. He's still great at bedtime, but naps are a different story. I found that sticking with the same routine is the best remedy. We have our routine for bedtime and naptime. Every couple of months our son will go through a phase of crying a little at bedtime or naptime when normally he doesn't. We start to panic and wonder if we aren't doing something right or needs us to change something. It's hard, but we always remind ourselves that the best thing to do is stick with the usual routine. After a couple days to a week, he usually straightes back out. In regards to your situation, if you don't have a routine at bed/nap time, you should definitely start one. Bedtime we take a bath, put on pjs, read a story and in the crib he goes. Nap is the same, but no bath obviously. Sometimes for naps it takes my son 30-45 minutes to fall asleep, but he's not crying just talking to himself. (I don't put any toys in his bed either.) Since you've started going into his room, you've started another bad habit for him. I would start going into his room less times until you don't go back in at all. Maybe you go in after 5 minutes, than 10 minutes, than 15-20 minutes, than not at all. After 3-4 nights, go in only twice, and so on until you don't go back in there after you lay him down. I know it's horrible to hear your baby crying out, standing up, shaking the crib rails (I've been there) but your son will get back to his orginal habits. When he's crying put headphones on and don't feel guilty. The amount of crying will shorten every night until there is none at all. I'm not a fan of the crying it out method; although this may sound like that's what it is, but I do believe the more you go in there the more they are going to cry. He used to go to sleep by himself before, he can do it again.
This age is hard because they are transitioning from 2-1 naps per day. Some days my son needs 2 naps and some days he sleeps for one nap and just talks in his crib through his second nap, even though he was yawning before bed! They are so curious and active and want to continue exploring everything so it's hard to wind down and go to sleep.
I think the key is consitancy and routine. I've learned that children will always go through something...teething, growing, etc., to disrupt their normal sleep, but don't change your routine! By the way, I'm not as strict as I sound. There are days we get home late or have people over so he goes to bed a little later, but we still follow the routine even if the bath is less than 5 minutes and he goes to bed without a problem. (Even on New Year's Eve with other kids still downstairs playing!) Good luck to you. I know it's a trying time. Just stick to your guns.