Oo momsh, normal yan sa edad na yan! Marami sa mga babies around 6 months na gumagawa ng ganitong movements, parang nag-shake o humihindi ng ulo, part lang ng development nila while they're learning to control their neck and head. A few of us moms noticed our babies doing this too, usually habang excited sila or exploring their surroundings. But kung sobrang frequent, rapid, or may ibang signs like hindi sila responsive o may fever, it's best to mention it sa pedia mo just to be safe and get peace of mind.