Inner quad/groin pain from running

Anyone ever had some slight pain on their inner thigh from running? It honestly feels so close to my groin and quad that I can't tell which one it is. 

I can run on it and it doesn't hurt at all during a run, but there's some weird discomfort after I run. I honestly feel it more when I'm walking or just moving around during the day, not when I'm actually running.

Any suggestions? Do I just need to stretch? Do I need to rest? Probably both. But I have my first 100 miler coming up in 3 weeks, and I really don't want to DNS it. TIA!! :)