Upper thigh pain

I’ve been experiencing some dull upper thigh pain on my right leg for the past month. It’s pretty mild, only really feel actual pain (probably a 3/10) when I do more higher intensity stuff (sprints) and that’s still not that bad. I took a week off running for vacation thinking it would go away with no exercise, but it’s still here. Mostly, it feels like a sore muscle but it just hasn’t gone away so just wanted to see what I could do to mitigate/strengthen it. Thanks!

I had some problems with my right knee earlier in the year so suspecting it’s related but not sure.