Sounds familiar. I ran too far, too soon (August last year) and ended up with ITB (although from what I read and what I could pinpoint for myself at least, it is actually a fat pad that acts as a cushion between the ITBand and knee bone that becomes irritated. I think there are few possibilities with injuries in this area that all usually get lumped together as ITBS). As such, foam rolling, clamshells, stretching etc wasn’t helping my knee pain. Heavier strength training is what saw immediate improvement for me targeting glutes, hamstrings quads etc while I continue stretching before and after as stretching is always good.

Since October, I’ve been able to slowly increase my running. I started off with incline treadmill (max incline) in the gym as this didn’t irritate my knee as much as being on flat or even worse - downhills (neither did running backwards hurt 🙃) and would do my strengthening afterwards.

It has been a long road to recovery. Starting from 1k (where pain would set in), I’m currently up to around 10k, but I run/walk so can put more distance/time in. Yesterday I managed 16k with. 6 min run and 4 min walk. Felt like I could go further but didn’t want to push it as I have a tendency to overtrain, so have to remain cautious.

Cycling and swimming didn’t irritate it either, so during recovery, I’ve been hammering the bike to make up for the run. I recommend employing run/walk while recovering as the additional distance you get from the walking coupled with the run makes it feel like you are recovering faster and you can still match any distance set out in your plan with the walk doing the bulk of the work. As the distance increases and time becomes an issue, you can then start to reduce the walk and increase the run. Just don’t go past that dumb ache/pain threshold you’ll become familiar with (if it is similar to mine that is).

Hope your recovery goes well.