Virtually any time a vehicle vibrates or shakes while driving (but not while braking) it is usually a tire or rim issue. The rotation of the tires did not correct or move the problem to the rear, so either the tires themselves are out of round or defective, or you may have an issue with a front hub (the part the wheel mounts to) or an issue with a front axle assembly. Have the shop double check the balance and runout of the rims. (they'll know what that means) and may take care of it for no charge.