Occasionally, I have to shift the car to neutral in order to start the car. Is this a common problem?

 

no, it is not.

 

shifter is more then likely out of adjustment (or has issues with it) (actually the neutral safety switch is)

 

Do you have to use the shift lock release? If so it is more than likely your brake light switch is intermittently failing... Next time it happens try and get someone to check your brake lights to see if they come on.

 

it could be a fuse