You should ask your boss this question, except phrase slightly differently.
Sir, I was thinking recently about how often I ask you for help on my tasks. I am seeking to strike the correct balance between solving problems on my own (and thus learning how to help myself) and completing work swiftly enough (which sometimes necessitates asking for help). I wanted to know whether you think I am striking that balance properly, or if I ask you for help too often, and you'd prefer me to try to work things out for myself more?
It's very hard for us to tell you here, both because you can't really communicate to us how frequently you're asking questions (and what your firm's culture is like), nor can we read your boss's mind - he may like that you ask questions, or prefer you not to; unless he's told you to stop bothering him (or given you nonverbal clues), he probably doesn't mind - but again, asking him is the best way to find out. If you approach it as a career development type of question, it's really a very appropriate one and should reflect well on your own abilities (both of self reflection, and understanding the different issues at hand).
It's also hard to tell (both for us and for you!) what the expectations are for an intern at your firm. Some places give legitimate work to an intern that they need accomplished in a timely manner; some places are more figuring out how useful you are and how quick you learn, and are going to prefer you learn on your own more (but not entirely) because they don't have the time pressure for the work. I guess you're more doing legitimate work given your description of the firm (I can't imagine a 6 person firm having a non-working intern) but who knows.
Secondly, perhaps partly off topic but hopefully relevant, some tips for asking for help in a useful way that might lessen how often you ask for help.
- Make sure you're asking complete questions, not throwing four or five questions at him about one issue. As much as possible, fewer interactions with more content is better. This means you need to do more research before asking questions, but that's not a bad thing.
- In asking the question, provide all of the information you've obtained in researching it. In addition to showing that you're not just asking him every five seconds, it also gives him some information about how you research problems; you benefit more from learning better ways to research questions in your field rather than simply having your problems answered.
- If you find you are stuck in a particular section and it's a major area of your field, consider asking either for an hour or two overview of the section, or asking to go to an offsite training in the subject. Sometimes you are stuck because you're missing something fundamental. Imagine learning to multiply but not knowing how to do addition: you would be lost, and have to keep asking questions, until someone realized you were missing the basics.
If you're doing these things, you probably aren't bothering your boss too much - or at least you're hopefully showing your boss where you need more training.