Just had the same situation. Called gas company.

They will find the leak for you, whether it's inside or outside. They found a leak in the stove and we then called an appliance company to check it out. The company suggested we replace the old stove. The county here has a new rule that reqiures a permit for the new stove. Home Depot or Best Buy call do that but the installation is now much more expensice than used to be (a few hundred dollars vs $20 a few years ago).