Yes - absolutely normal. DS started around 15 months too and is just starting to get better now (coming up on 18 months).

I think a big part of it is frustration over not being able to communicate - he has definite needs now and definite WANTS, but he can't verbalise them. Since he discovered some more words (drink, grape, toast, cereal) it is getting better - but he still gets frustrated when he doesn't get his own way.

It's tough. Hang in there.