Russki

So I'm trying to figure out why my brakes are so tight/hard to push (still brakes). I've tried a couple of test like seeing if the brake booster still works and it does. So I'm curious to see if its the check value I need to replace or not but I'm not 100% sure. I'm wondering if anyone else has had this problem I've tried searching the forums with something around the same problem but not really what I was looking for. Can anyone help me please?