Sometimes you find you have a room that is too hot or too cold this may be an airflow problem. Is your blower on the right speed setting? Is it sized correctly? Are the blower, filter and coils clean? Are there return air grills in each room? Is the ductwork sized correctly? These are all things that will cause airflow problems. Sometimes air flow can be adjusted or Balanced to help if the blower is ok and sized correctly, Sometimes it takes more like changing ductwork. The first thing is too try to adjust the airflow by partially closing some registers or dampers and try to force more air to the problem areas. If a room is too hot usually you can partially close the register and see how that does. Sometimes it takes a few adjustments to get it right.