Mh thats a hard one.
Especially since I wouldn't really mix burnout with the missing of motivation.
Burnout is rather something that you experience, take a day completely off for recovering and do mindless stuff and all will be fine.
I experience only once a real burnout. I was sent to a branch office, where I had to clean up the mess of an colleague. I misscalculated the work and planned 4 days for it. The first day it was clear that I was slower than I thought and had to really go 200% on that. I barely finished within the time period with the result that my brain just stopped functioning.
I couldn't do the simpliest math, or even use the computer as good as before. That took me 2 days of watching brainlessly tv and movies to recover.
That is the burnout I experienced. Something you can recover out of but you shouldn't let it happen. It is important to just stop thinking about work, beeing an creative mind the thing we do is usually ONLY think about work.. but that will kill you after sometime especially if you are slower than expected. If you like thinking about work, fine but try to add areas where you think about work and where you think about other stuff. Like "In front of pc = work" "in front of tv = relax" or something
The lost of motivation is something different I guess, I started so many projects and stopped working on them.. just because my priorities changed in this time or I got depressed because I had other things to do and thought I couldn't get anywhere with it anyway.. or just got bored of that idea that once seemed so awesome to pursue.
There is no treatment for that... you just have to make limits. Like if you haven't done anything for that project within a week.. drop it.
Okay I hope this is actually helpful.
and to that teamwork thing. I find it very comfortable having all the people in a instant chat group like skype/whatsapp(especially whatsapp since most people have a smartphone and look at it every minute
) and spam them ideas every single time you get one and manage all the files within dropbox.