Opening Hours, Berlin
I just read mccrorj's local custom tip for apotheke's in Berlin. I wanted to add that every pharmacy posts a list of which pharmacy is on call. You can go to your nearest pharmacy, check the list in the window and find out which one in the neighborhood is open. Pharmacies at major train stations in Berlin stay open longer than your average pharmacy, so if it's before 8pm, you might be in luck there.
Also, note, grocery stores do not sell aspirin/bandages/tampons and the like. Best bet is to go to a drug store, a Drogerei, not an Apotheke, for these things. There are lots of these around, my favorite being at the various large train stations...(Zoo, Friedrichstrasse, Hauptbahnhof)
If you come from a 24/7 culture remember that much of berlins stores still closes on a sunday. This generally includes the main stores such as the Galeria Kauf Hof and Kah Da We. Don't worry the tourist shops stay open to take your money. The Pharmancy (apotheke) is however closed and they operate an on call service but you have to find out which one is actually on call.
Most businesses/shops open between 9-10am. Certain offices might open earlier.
At the bigger shopping-centres and malls shops are open till 8 pm on weekdays and Saturdays. Other smaller shops within the city often close at 6:30pm.
Malls are generally closed on Sunday. But I've seen on some websites that a few plan to open on Sundays during the soccer world cup.