Hoping someone who has had ITB / knee issues can help out.
At the start of April I picked up ITB on my left knee.
Bike fit + physio + stretching + easing back into it meant cycling was pain free in a couple of months.
Now though I’m encountering quite an odd phenomenon; on the bike my knee is fine but a few hours after a ride I’ll feel a dull ache or soreness in the typical ITB region.
The odd bit is that after one ride the left will hurt, next ride it’ll be the right.
We’re talking 2/10 ‘pain’ so nothing crazy but can’t help but think I’m aggravating something.
In my experience, ITB pain is often the result of weak glutes. You can’t stretch it out, roll it out, etc. the leg is a long kinetic chain and where you experience the pain may not be the source of the pain.
Focus on gluten strengthening exercises….single leg squats (eventually do them on a balance pad or pillow), bridges w/ leg lifts, monster walks with resistance bands (both straight leg and bent legged), etc.
Basically any exercise you can do that causes the dimple of your a$$ to burn is a good exercise to help remedy the issue.
I did my IT band in circa 2008 (I forget fortunately). According to the physio the left leg trying to compensate for right had become taught and pulled the right patella out of alignment and it was like a chain saw rubbing against the bone The physio had me doing exercises to loosen and strengthen my glutes like @Power13 says. That basically managed it for 5 years with it bouncing from side to side but no more than a level 1 or 2 pain. A bike fitter diagnosed different leg length (shimmed the shorter right) and that seems to have sorted it permanently (at least for the last 9-10 years).
This advice has worked for me. Also, you must do EVERY day, better yet a couple times a day particularly after you ride. Continue after pain is gone for at least a couple more weeks. (I use 2 tennis balls taped together).