Security system?

I had a shortage in the ignition wiring fixed a year ago by a driveway Mechanic he just cut the short out a replaced it with a new small wire. But the car will start up at first but if I go into the store an come out an try to start it won't make a sound it will not start, after sitting for an hour or so it will start like a new car. I think my security system is acting up what can I do?