Hi, i learned Wild Eyes by Parkway drive, and i don't know how to palm mute properly for that speed,i need to make chugs of up and down strum, but when im palm muting my hand gets a bit too stiff and it kinda mutes it too much, how can i palm mute but still get a decent sound from it? i usually put my hand between the bridge pickup and the bridge, but every time when i have to strum fast my hand becomes stiff, and im squeezing the pick too hard too. , can you guys tell me some tips and tricks for fast palm muting?
It's practice, practice, practice. If you're used to being a wrist or arm strummer you may find issues you have to work through, but you'll get the hang of it quick.

Rest the side portion of your hand running down from your pinky next to the bridge, so that you're making contact with the meaty portion. Then you'll be strumming mostly with your thumb and index finger. It will look like all you're doing is extending and curling your thumb, and in a way that is almost correct. The entire motion becomes your hand, so you'll have to build up strength and accuracy in those muscles just like with anything else in guitar.

Good luck! It comes pretty fast once you get the hang of it.