I've been trying to solve this for ages now, i've looked at threads and different websites. I've partially solved it.
The problem was whenever I entered a value (such as 1) into the channel box for one of the blend shapes the character would move to where it was when i created the blend shape. They way I solved this was I went into inputs and changed the order, and I put the blend shapes input below the skin cluster. (character is fully rigged and skinned.)
That fixed the problem a little bit, but now when i enter a value the character moved up in the Y axis a little bit.

I don't know what to do, thank you!