Overuse hip injury?

I keep getting hip achiness (mostly in groin). My glute also gets a tight feeling right at the end of the butt bone. Its not a sharp pain and it doesn't hurt to walk/run with both groin and glute. But it aches from time to time. I usually get it after a race. For example, this time it was after running a 5k one week after running a marathon. I was fine after the marathon but it came on the next day after the 5k. I was running 80mpw before the marathon. The other time was after a 10 miler in March then doing a track workout a few days later. I had to take it easy running for 2-3 weeks (only ran 2-3 times) and it slowly went away.

I can hop on it no problem. The only symptom I have running is my outside hip gets tight and I feel out of balance. But this goes away after 2 miles or so.

I did get a massage before the marathon and my pelvis was out of alignment. So maybe its from this? The 5K had some steep hills so maybe I knocked it out and its pulling on my muscles. But its still bothering me 1.5 weeks later. Its not getting better but not getting worse either.

Maybe its just my body telling me to rest. Any thoughts?

I should mention I didn't rest at all after the marathon. I know pretty stupid.

My other thought was stress fracture but I can't imagine that I could just take a few weeks off (like I did in March and last November) and go back to running 50+ mpw for 6 months. Hip labral tear? Same thing....I can't imagine I could pull this off. I did see a ortho doc in March about it and he didn't think it was a labral tear based on my range of motion and symptoms. He thought it was a inflammed IT band or high hamstring tendonitis. But most of my symptoms have been in the hip flexor region.