I want to do an independent dissertation type research project, not being part of a uni, how can I find out if my Question has already been answered?
To directly answer your core question, "how can I make sure my research question hasn't already been addressed/answered by previous researchers", the only real answer is a thorough literature review and an associated deep understanding of your research area. This is universally true of all research disciplines; knowing what others have done and learned before is a fundamental part of conducting research that advances human knowledge. If you just want to investigate something for your own personal interest, then this is not completely necessary, of course. But rediscovering something already known within a field may mean your research is not of interest or able to be academically published.

There are other dangers of not knowing background before you start, of course. The simplest is that you go about things wrong, and previous researchers have established that your approach is fundamentally flawed, dangerous, harmful, or otherwise inappropriate. It may be that others have done almost exactly what you intend to do, and you may simply be setting about to replicate a previous study. Replication is fine, but replicating something already found out to be flawed or insufficient to answer the key research questions may just be an exercise in futility. 

As mentioned in the comments, there are major ethical issues if your proposed research involves human participants, such as doing sociological/anthropological work. This includes activities such as asking questions, giving surveys, and reporting on naturalistic observations. At best, not observing certain precautions and methods can mean no legitimate academic publisher will touch your work, and others in the field will reject it entirely as unreliable or unethical. At worst, you can do real harm to others and get yourself into serious trouble. Understanding and applying principles like informed consent, protection of privacy, respect of autonomy, etc, are important no matter what your goals are. Working with "at risk populations" (which can include indigenous tribes) requires an extra level of care, and may even have legal requirements of registration and authorization to be acquired in advance to avoid criminal proceedings, fines, or more.

But back to the core question, there is no simple, fast, or easy way to see if a question has been asked and/or answered before. It simply requires intimate familiarity with your field and line of research, preferably assisted by speaking with a network of fellow experts familiar in the field, and a lot of searching and reading through work on your own to determine what is and is not an open, interesting, and potentially answerable question. If your field has "survey papers" that explicitly call out a certain area as an "open area of inquiry" or an important question for future research, that's certainly a great place to start! But how exactly to conduct a good literature review is beyond the scope of this forum, and requires intimate knowledge of your particular field. You can start with Google Scholar and some clever search terms, but even knowing what terms to use is often a highly field-dependent issue. It is not insurmountable, but you should at very least be aware that this stage of research is both very important, very time consuming, and will require a great deal of work if you are not already deeply well versed in your field of inquiry.