i have a 1000 mah 25C 3S battery, when i charged it for flying it was 11.92 volts, but as my plane crashed it was lying at this voltage for like 5 days. then today i checked it and thought may be it will go bad so i put in it a old waste plane and burned it upto 10.4 volts, is it ok for storage.

i am also thinking to get a nice charger with all those features like checking a battery balancing and program for storage too. can anyone suggest that charger.

This is amply discussed before, please use search.

For example, see item [5] in the first post here : http://www.rcindia.org/batteries-and-chargers/taking-care-of-lipos/

Almost all chargers with a 2 line LCD display (50W or higher) now have this feature.