2000 Kia Sportage Water Pump

My Kia is making a grinding noise under the hood. My heat is also not working. I had my radiator flushed and the thermostat replaced when the heat first stopped working. It worked after that for a little while but it stopped working again. My heater coil is fine no leaks on the inside of my car but I noticed when the heat stopped working my car would run really rough especially sitting at a light. When starting my car in the morning or after sitting for some time the engine reves really high around 2 1/2 RPM and continues to go higher untill finally slowing down. Does all this have to do with my water pump and the water not being able to properly circulate through the car? Please help me I've been having problems with this car since my warranty ran out!