how can i find electric short from room to fuse box?
My approach (not an electrician, just a guy with a meter) would be to start by mapping the circuit (find all of the outlets and fixtures that are on it), then unplugging EVERYTHING that's plugged into that circuit and see if that has an effect.

Next up, I'd kill the breaker and open up the switches and take a look. See if there's evidence of burning or arcing, or if one switch feels different than the other. I'd probably disconnect both switches (safely capping all wires), then turn the breaker back on and verify (using a meter) that the voltage is reasonable at all the outlets and other fixtures, and see what happens in the bedroom. 

Basically if that tells you nothing, then I'd either start pulling outlets and fixtures off the circuit (kill breaker, remove outlet, capping wires, breaker back on) until I figured out what the heck was wrong, OR I'd just call an electrician.