Hi Lise,
I've had some of my own concerns with my DS who is 17 months old, except that he is flapping his arms and kicking his legs when he is super excited or really frasturated (tends to do it more when he's tired too). I was really concerned about it so my DF and I went to see his paed and he told us that his opinion was that he does it mostly out of frastration as he can't really talk yet (only has a couple of words) so that's his way of communicating his feelings. He said that he'll probably stop it once he's walking. The point to my story is that he said other toddlers bang their heads, throw their head back, or rock back and forth. He said that toddlers express their emotions in different ways. My DS has his molars coming through too, so is not sleeping great ATM, although there has been an improvement of late. Regardless of my paed's opinion, I am still planning to get him assessed in case there is some sort of problem/delay that can be fixed/helped. He's been late in rolling/sitting up/crawling/walking so I want to make sure that if some sort of intervention is needed we are on the ball. GL with it hun, but if you are worried go and see your GP or even get him seen by a paed if you're still worried.
B.