Resuming running = pain

After 4 weeks of de-training from an IM, I started out for a run today. I didn’t make it more than 1 minute before I started feeling some pain around one of my knees and stopped to avoid flaring anything up badly. I’ve had IT band issues with that knee before, but this wasn’t the same kind of pain. Best described, ITBS was like a sharp needle, this is like I just hit my knee against a wall and the whole thing hurts.
I wasn’t totally stagnant the past month, I did a short swim, bike ride, and easy run (all separately!) along with occasional stretching. I don’t think it would be common to take 4 weeks off after a successful season only to come back with an injury, but I thought I’d ask if this is expected? Is there anything I should have been doing to recover better?