Player (box) movement is shaky (visual only)

I am kind of a newbie (~ 1 week of experience).I am trying to make a game where you are a box, everything was working, but suddenly (without (i think) changing anything) it started (only in game view) "vibrating"/going up and down while only going in a flat surface.But the thing is i tried replicating by stepping its update and the coordinates of the cube seem to change smoothly.(same for the camera)

Notes:

• The box doesnt have a riggid body

• The camera moves using a script ( copying the players cords + 10 units)

I don't think code sample must be given (i will if you want) because i dont think that its something wrong in my script (i believe i would have found it). P.s. Sorry for my english.