In conventional design, you would never apply your +5v to your switch. The +5v should NEVER leave your PCB, or be connected to any unnescessary component. It's valuable, you don't want to corrupt it, or add noise to it, because it could affect the operation of your PIC.

A better connection would be to have the COMMON of your switch going to Vss (0v), with either side to your PIC pins as before. You then only need a SINGLE Pull-UP resistor on each pin going to +5v. 10K is a good value.

The control logic is then INVERTED... ie the pin goes LOW when there's a switch on it... eg...

TRISB.5=1
TRISB.7=1

Loop:
If PortB.5=0 then goto DriveForward
If PortB.7=0 then goto DriveReverse
Goto Loop

Since you're experimenting, why not dispsense with the external Resistors and invoke the INTERNAL WEAK PULL-UPS that exist on PortB?

TRISB.5=1
TRISB.7=1
OPTION_REG.7=0

Loop:
If PortB.5=0 then goto DriveForward
If PortB.7=0 then goto DriveReverse
Goto Loop

Look in the PICs Datasheet to find the OPTION Register to see what that instruction does.