Will not shift into reverse

My Tata Indica 2008 model does not take reverse every time after driving on gear five, but if I am driving on gear four, reverse will be fine. Today I was rushing to town and accidentally drove in gear five, I had to push the car after I have parked in order to reverse it and drive of the parking. It once locked all the gears one day except gear five after trying to change down from five in order to stop. Help me.