Agree with both above. Cattle do dominance with rubbing, pushing with their heads.
Unfortunately, correcting may not b e possible... and the only way to even hope to stop it is to get rather aggressive with him and to NOT let him rub his head on you ever again. Also agree that if he is going to run and all that, he should not b e given any type of affection until he is calm and quiet.
Does he have anyone else (bovine) in the field to play with? He is starving for the typical interaction with other cattle.
If he was mine, he would be taught a few lessons with a good crack across his nose when he tried the pushing... rub his neck and his sides all you want... NO PETS OR RUBBING of the head face on... EVER with any type of animal like that... Look at all the pictures of bulls fighting, deer, rams actually ramming each other... goats doing the head to head stuff... mature males ... fixed or not.... have to dominate and the way they do so is head to head....
The thing is, he does not want to be mean, he simply sees you as his playmate, someone he can and will push around... this is typical behavior for a steer/bull/ram/male of any breed and does not have to be intact male... he wants to play, his play is to dominate whatever he is playing with. It will not lessen...
Stop it now,,, or get rid of him. Sounds to me like he is the perfect size to be beef on the table... harsh as that might sound.