why does my oil light keeps coming on

It really depends on which oil light you are seeing. Is it your maintenance minder light? Oil level? Oil pressure light? It's a good idea to check your owners manual to be sure you're not driving with low oil pressure. If it's the maintenance minder, that is usually manually reset by the shop that changes your oil. Sometimes instructions on resetting the light are in your owner's manual 'maintenance' section. Be sure all of the maintenance is performed for that particular mileage interval before resetting the light