I’m wondering if the change in running surface + worse daily sitting situation could have led to my ITBS or if its a “true” over-training situation?
It sounds like both.
I have the same issues if I take a lot of time off. I have to be careful when I start back up because too much too soon leads to problems. I also have a very low tolerance (both physically and mentally) for road running. I think it’s because it’s so repetitive, and I came to running quite late.
To counteract the tightening tissue, check out the Starrett book, Becoming a Supple Leopard. There are lots of painful-but-beneficial exercises in it that will probably solve/reveal any issues.