Hello my name is mike

Oil getting into your radiator could be from a leaking head gasket. Get the coolant system pressure tested and that will help you find out if there is a leak in the coolant system. The reason the oil ends up in the coolant is because the pressure that the oil runs at is much higher than the pressure that the coolant runs at. But at the head there are oil and coolant passages that can leak into each other if the head gasket is bad. This will cause; misfiring, overheating, smoke coming out the exaust and other issues.
So, it is important to make sure the coolant system is holding pressure. Unfortunately if it is a head gasket it will not be cheap to repair as the head must be removed and a new gasket replaced then re-assembled. It can cost hundreds of dollars.
So, doing the coolant pressure test will not cost so much and it will tell you where you stand as far as the head gasket being good or not and you will probably find where the oil is getting into your coolant. If the pressure test does not locate the leak, you may have to have a compression test done on the cylinders to check if the head gasket is sealing the cylindr pressure at least and that no coolant is getting into the combustion chamber.
Get the coolant pressure test done first, then if you can't find the leak ask the mechanic what they suggest to find the leak where oil is getting into your coolant. This will lead to a big problem like the head gasket leak if it has not already. Ask the mechanic if they think the head gasket might be leaking.