What could the problem be on a 97 dodge ram if antifreeze still leaks badly even after the thermostat has been replaced and the radiator and pump was pressurized by a professinal and found no leaks?

Where is it leaking? That pressure test sounds funny, why would you pressurize only the pump and radiator? If you are leaking coolant outside the engine, locate the source. If you are losing it from the radiator but cannot find a puddle suspect a head gasket problem. Check the Radiator cap first, if it is bad high pressure coolant will travel back to the overflow bottle.