my 2008 Honda Civic Sedan, rocks back and forth while I am getting down or, if I push it slightly, Is it normal?

i don't remember this happening earlier.

3 weeks back, my car went off the road, and was stuck in a lot of mud.

after that, i had the tires aligned, rotated...and power cleaned.

the service guy told me that, the control arm is slightly bent and i should replace that.

Could it be the reason for this behavior?

 

Front to back or side to side?

 

Front to back.

 

That's normal. The Park setting engages a tooth in the transmission that can let the car move slightly forward and back before it catches the next tooth and stops. That would really only be noticeable on perfectly level ground. If the car is parked on an incline it will naturally roll until the tooth catches and stay still.