Have you been given a magical/spirit name? Was it given to you or did you arrive at it yourself? Was there a mechanism involved (ie the first two things you saw on coming out of a tent)?
No, I don't have a magical/spirit name. I have on one occasion used a name that someone else had dreamed of as a name for me, but I'm not sure I'd do so again.
What purpose do you think having a spirit/magical name serves?
I can imagine several purposes. Anonymity/separation from one's everyday/legal name, especially when you have reason to assume that your spiritual inclinations wouldn't be looked on favorably by your neighbors and/or family and/or boss. In that sense, "Cat" is such a name because it's the one I use when I discuss spirituality online.
I think I have also heard of special names granting a special kind of protection as long as nobody but your spirit guides/allies knows it. The flipside of this coin would be that knowing one's magical/spirit name would give you some kind of power over them. Since I lack personal experience with that kind of interaction between magical workers, I don't see a need for such a name for myself.
I can also see how a name change could express/make official a change of one's path, but that would apply more to a legal name change than to the adoption of a (secret) magical/spirit name. For me, that's what self-applied "labels" are for, if and as long as I need them, so no need for an extra name.
Along the same lines, I understand that some people (like PathWalker has described) adopt a new name (secret or not) to express a spiritual ideal for them to strive towards. Again, this is not for me, so, again, no need for a different name.
And then there are some more problematic reasons: Because "everyone" else does it (or at least "Special Person X" does). Because it seems to go better with the (pseudo-)historic clothing that some people wear for spiritual purposes. Because it makes one feel special. All of which may of course occur in combination with any of the above-mentioned reasons.
The second reason for asking relates more to titles rather than spirit names.
What is your gut reaction (I am a strong believer in gut instincts as long as they are not mixed up with personal grievances) to the following title for a teacher?:
Reverend Elder Pathfinder Shaman
My gut reaction? This: Bwahahaha!

I would never take that person seriously as a teacher. Way too much ego in there.
I accept that "Reverend" is a title that some religious organizations give to some of their members (which may or may not mean these members have any special qualifications). I accept that such a title may be necessary to be allowed to officially perform specific rituals (like weddings) in some areas of the world. So that alone doesn't bother me all too much, although I also wouldn't think any higher of a person with the title of "Reverend" than I would of anyone without it unless I knew what exactly they had to do to get the title.
But the rest of the list just indicate a rather big ego to me. Maybe that person is indeed regarded as an elder by their community. Maybe she/he really does a shaman's work for their community, warts and all. But even if that is the case, why the unnecessary capitalization of these terms? That just suggests that there is an universal organization out there that has the power to grant such titles after a regulated examination of the applicant's capabilities. And such an organization simply doesn't exist (and I think we're better off for it).
And "Pathfinder"? What is that even supposed to mean?!
I'd rather learn what kind of WORK someone does and what services they perform for their community on a regular (and recognized) basis. That kind of (verifiable) information tells me a whole lot more of what I want to know to decide if someone is trustworthy than any list of fancy titles ever would.