Tantrums

Hey mamas ! So, my baby boy recently started not wanting to sit in his high chair for eating, will throw tantrums, same with carseats, and i feel it’s all of a sudden happening. Even feeding him has been a bit struggle 😅 until a few weeks ago, i didn’t have any of these issues. So my question is, lets say when your baby doesn’t want to sit in his high chair, do you just let it go, or this is the time i have to be a bit more assertive. I’m a first time mom and this is all new to me. Not sure if this is just a phase or not 😌