overheating and when first started light white smoke or steam coming from the exhaust

My car over heats. Gauges say hot, air conditioner low, engine idle, etc. I have replaced thermostat. Did not have one originally. I replaced reservoir because it was leaking. I made sure purge lines and bolt was clear of blockage. When overheating, my top radiator hose gets really hot on bottom of hose and just hot on top of hose. Hose gets really tight. Same thing with bottom hose. When car is hot water and steam come from overflow tube on reservoir. Heater in car only comes from floor or defrost and it is not hot. Air conditioner is not cold, but blows from vents. Light white smoke or steam coming from muffler when first start.