1996 Honda Accord Engine running very hot just after oil ch

The car engine temp was perfect just prior to having the oil changed, new tires and alignment two days ago. When I drove the car away from the shop the engine began to overheat and continues to overheat unless the car is moving. The temp gauge will fluctuate from under the half way mark while driving on the freeway to nearly in the red zone when at a stop light or in stop and go traffic. Turning the heater on full blast lowers the engine temp dramatically and very quickly.

I'm thinking it may be the radiator??? Could it be the type of oil used with the oil change? It just seems too coincidental that this is happening immediately after the above work was done on the car.

Thanks in advance for any help!!