Hi,

If you are not overloading your PIC it should not heat up. Unless you are logically doing a short circuit. With the 1k resistors going to the base drive the PIC should be driving around 5ma and each port pin can drive something around 25ma.

I still need some info how you have hooked your half-bridge to the PIC. Taking your schematic into mind, if you cannot draw one please mention by text. Explain your half bridge as left part / right part and then the connection of the PIC to the NPN/PNP. I would draw up the schematic for you and then analyse.

You can also play with the TRIS bits to simulate a Z output (Tristate High Impedance style). Thus you get 3 states 1,0,Z.

Even if everything is electrically okay, motors can sometimes draw (they normally do) huge starting currents. This may trigger the brownout reset inside your PIC. One option is isolating the PIC supply from the motor. Or you may use (2+2) 4 general purpose diodes (say 1N4007) to power your PIC and Motor separately and having your PS at 6 volts. The two diodes approximately drops 1.2 volts so your PIC runs at around 4.8 volts. That means 2 diodes in series powers the PIC and the other two powers the driver. So your decoupling cap for the PIC is used for PIC only. (The drivers need them because if your driver is at 6 volts and your PIC outputs a 4.8 volt at logic 1 it is still going to fire your PNP transistor)

If you plan to use higher voltage for the motors then do use optos as they become your level translator.

This is not as complicated as it might look but I need to have the schematic exactly to understand possible cause.
(Temporary Variables in my mind are limited due to a faulty design by GOD)