Hello Deborah, we haven't talked before, so nice to meet you (I love your lo's name, btw :wink: )
OK, a couple of things spring to mind from your post. Can you post your routine for us, so we can help with more details?
-It sounds like your lo could possibly be overtired when you're trying to put him down. How long is his awake time? Have you tried shortening it?
-I used to have a similar problem with the back arching, and it took me ages to realise that my ds didn't like being held when he was trying to wind down for a nap. He preferred being cuddled, then placed in his crib, and then go through the ssh/pat. I think it annoyed him that he couldn't get comfy on his own. BTW it took a few attempts to get this to work, as it wasn't how he was 'used' to going to sleep, but it's worth persisting with, as it eventually worked.
-I also found that if I backed off a bit, that helped. We did the wind down routine, then he went into his crib as I described, but then I backed off, and he preferred this. Again, it took many attempts but eventually it worked.
-Yes, ds will only nap if his room is pitch black
-Have you tried ssh/patting? Some babies (and your ds sounds similar to mine) are annoyed by rocking/pacing the floor/etc, and it winds them up rather than settling them. If you need advice on this, let me know, and I will do my best.
Don't give up! You can do it, you just need to find the best way for you and your lo.
HTH