i started my car but, it was difficult to enter gear. what could be the fault?

Is this for a manual transmission? You could be having an issue with the clutch master cylinder or the clutch slave cylinder. Check under the hood for fluid level (facing the car, it will be the smaller reservoir to the right of the brake fluid) and also check under the dash for signs of fluid leakage where the clutch pedal actuates the master cylinder push-rod. You may also want to have a local shop take a look at it. Try the link below! http://repairpal.com/mazda-within-10-miles-of-virginia-beach-virginia-23479