Wounded Duck
You were told wrong!

jason m
it should be cool you were told wrong

Thor
If you are cooling okay don't worry about it. It can depend on the distance from the compressor. I can guarantee that closer to the compressor it will be warmer. Close to the evaporator coils and far from the compressor it is fine for it to be cool even a little cold. It may be only the cool evaporator radiating back on that line. As long as it is not dripping water or frosty you are fine. If the high side line is frosting, and you are not cooling, that generally means you have lost enough refrigerant that the gas is evaporating in the line before it gets to the expansion valve where it is supposed to evaporate. Don't worry about it. In fact it may be a good thing indicating your condenser is doing a very good job of exhausting all the heat so it is cool by the time it gets to the air handler.