Is it normal for a man in his early 20s to get lost in a place he is familiar with? for example, i was in the shopping mall yesterday heading off to the pharmacy. however, i went to the wrong floor and had to ask someone to tell me which floor it is.

Depends: I know there have been times in my life where I might be thinking about something intently and get lost where I am at. So, if this is a single episode then I would not worry too much. However, if this is a recurrent issue then that is not normal and would recommend evaluation.

Depends on details: In general, everyone gets lost or disoriented in a modern shopping mall sometimes. That's why they have the maps and store listings at various locations in the mall. Most people visit a variety of malls and go in and out of many stores, meaning it's common to not know north from south, or left from right, inside a big mall. The harder thing may be trying to find your car after you escape the mall.