When i plug my jack into the amp and my guitar (esp max600) i get a really loud output when im not even touching the strings, it was fine before, no sound hardly. When palmed its silent too. It has a passive SD distortion pickup. When i first got it it wasnt like this at all.

Any ideas?
Sounds like the ground wire to the bridge has come away.Easy fix if you are handy with a soldering iron if the wire should be soldered.Even a shop shouldn't charge you much.