i have the solution ..... first open your iphone4, tail lamp cover removed ... uses a very fine tip screwdriver ubicated after the button below and above the power switch, position the screwdriver and gently press down a little ... Now blow with your mouth or a can of compressed air .... Test your button and go .. apparently it is dust that accumulates between the switch and the button
Answer to: Power and Lock Button Stuck, Requires Heavy Pressure