The tank will have nothing to do with the pumps pressure capabilities. If the pump cant get past 58 lbs. thats all it can do. If you bought the tank at the same place you bought the plastic pump, chances are it is bad.
You must check the air in the tank when the pump is shut off and the gauge is at zero.
It sounds like the pump is mounted on the tank, so it's hard to do the lean test on the tank to see how heavy it feels.