How did you get this far and not know how to pick research topics?

Pick something you're passionate about that has not already been explored 8 billion times and run with it. Find an intelligent angle and more the subject along. Don't try and create something new.

If that's too hard, maybe try and solve homelessness with street furniture and shipping containers.

Every thesis project I've seen can fit into one of two categories:

1) Using design to solve a problem.

2) Using design to make a generic space for other people to work in to solve a problem.

Avoid the latter. 

In my program our thesis was split into a research semester, and design semester. I'm not sure how other schools do it, but we were allowed to start very vague and slowly narrow down as we researched more and more. All we had to start with was a paragraph about what we wanted to explore, and after being assigned an advisor we went from there.

A big issue I had, was not standing up for my original idea, and ending up on a path I didn't want to be on, and couldn't get off. 

To add to tduds, there is a third option

3) use your thesis to figure out what matters to you in architecture, like Robert Venturi

https://mitpress.mit.edu/books/how-write-thesis

Take a look at how poorly sustainability is typically applied. Or how often owners will drop it once price is discussed.

That's a good #3, Josh.

In the PNW you don't see a lot of that. Most of what I review is overly socially conscious, sometimes at the expense of an actual design.

It's weird to be studying architecture not being passionate about anything specifically. I sort of had the same thing, I was interested in so many aspects that it felt like focussing on just one of my interests would exclude all other options. This meant that I did a lot of different design studios, that approach architecture from different, often opposing angles. It made me question everything all the time, quite exhausting actually when it came time to choose a thesis subject. Graduation was therefore quite a struggle since I tried to combine everything in this one final project, my magnum opus. Needless to say it didn't work out the way I imagined. So I would advice not to put too much pressure on yourself in determining a thesis subject beforehand and use the thesis to determine the subject for you, focus on the route and not the destination. 

I went with the third option too. My project was a vessel for the ideas, and outside of a purely pie-in-the-sky thinking by the Columbus Indiana Architectural Archives, wasn't attempting to solve a problem.

Mine wasn't a thesis, it was called a diploma project because it was for a B Arch but it was for the design of an architecture, engineering, and interiors firm within a large existing, almost ruinous, structure. It wasn't pinned up on the wall but was about a 20' by 40' floor space that was laid out like a crossword puzzle of interconnected scrolls of trace full of drawings laid on the floor that then became a stage space for the performance of my presentation where everyone got up and walked around among it and over it. Entirely done on trace paper. Never made it into my portfolio because it was more or less a performance piece, not some restrictive silly design boards or dopey flat computer animation. Got to explore everything I wanted to. Professor hated it. Jurors loved it. 2nd highest grade in the class.

Easy!, I was redy to be done and move on to the next life challenge! thesis isnt rocket science, all you do is make a statement and then defend it with reasons why such as;

this building is great for the blind! why PoLoBreak? tell us more!!!, because I dont have any sharp corners that a blind person can bump into and be severly injured or concussed which is the leading cause of all concussions by blind folks btwn the ages of 4 - 92, and now their love one's will be at peace cuz im out here in these streets makin architecture that will lower concussion for blind folks. bang bang!!

My thesis was really really long.  Too long.  I became a bit obsessed and over did it a bit.  Got an A, but in retrospect I think I had a really good idea imbedded in a bunch of fluff...at the end of the day the main point kinda went under the radar.  had I focused on that single idea, it would have been very strong imo.  Point is, focus and stay focused.  

This was basically my thesis: 

http://archinect.com/news/article/149983413/china-will-build-modular-housing-factories-in-the-uk-aiming-to-produce-25-000-homes-per-year

I should've stuck with it after graduation.