Hi mama! Ang head shaking sa 1-year-olds ay usually normal lang, maraming babies ang gumagawa nito out of curiosity, or as a habit, or kahit para lang sa fun ng pagkita ng mundo differently. But since every baby is different, I'd really suggest checking with your pedia just to be sure, especially if it's very frequent or may kasama pang iba like stiffness or hindi normal movements, one of my mum friends noticed something similar sa baby niya and the doctor put her mind at ease agad, so better safe than sorry!