TL;DR my knee seized up and was very painful during a run 3 years ago and now I can’t run more than a mile before my knee locks up with the same pain.

I (36m) used to do a lot of triathlons and during the lockdown my escape was to run. I was doing pretty well in my splits and my fitness level was at an all time high and so I decided I’d add in some body weight exercises. The day of my injury, I did some lateral leg raises and went for my run right after. At about mile 7, I could feel tension building in my hip, down my IT band and into my knee. I pushed through and about a quarter mile later, my knee seized up to where I couldnt walk bending my knee. Now, I can’t run more than a mile without it seizing up, If I ride my bike for too long, it starts to seize up, I can play basketball for about 1.5 hours without any issues but anything over that and I start to feel it as well.

I have seen physical therapists, orthopedic surgeons, and chiropractors trying to figure out the issue. All have asserted that I don’t have a tear (no pain when the test for mobility) and that it is likely an IT band issue. I’ve done the therapy, done the stretching, rolled up and down my IT band/hip flexor and can’t seem to get permanent results. Sitting here, writing this, I can feel a dull pain from my ankle, through my knee and to my lower back and just the one side where this occurred.

Would love some advice - I am, admittedly, not flexible (can’t touch my toes), I lift weights 5x week, play basketball 2x per week, and stretch before and after each activity. I miss running. I miss cycling.

Apologies if this is the wrong place to post this but appreciate the help! Happy to answer any questions that may get me to a resolution.