If the tank has more air pressure than was put in it, and still has water in it after emptying with a faucet, then the bladder in the tank is probably broken. Running a faucet of 1 GPM or less will cause the pump to cycle, but it will be a slow cycle. Pressure switches usually don't change there setting unless they froze or got hot when thawing with a torch? With the power off and the tank drained, make sure your gauge goes to zero. All of this can be caused by a bad tank. Take the tank off. If it still has water in it you need a new tank.