Kicking, hitting, pushing

Yes my son has has started hitting kicking pushing what seems like out of nowhere. I thought it was pre school and him maybe copying other kids but maybe it’s a stage they go through at this age reading this? X

Firstly, it's completely normal. Your child still has next to no impulse control and their actions speak of their emotional state. All behaviour is communication and all communication is valid. Your child is trying to communicate something, with still limited understanding of the world and ability to express themselves. Validate the feeling 'you seem frustrated/angry/sad, can you tell me what made you feel like that? Did you want me to move my leg? Do you need more space? Can you tell me with words so I understand and can help?. Pick a phrase or two, don't condemn the action just try to figure out the underlying need and show them another way to communicate that need without shame and definitely without punishment. It takes time for them to learn impulse control, in fact it actually doesn't fully develop until adulthood and even then who has full control all the time?