Weird pain in my quads?

[Bergboy123]

Hey guys, I play tennis every day, work out, etc. So this is a little weird for me.

Here's what's up. I've been doing barbell squats for a few months, but last week the day after I worked out when I was playing tennis I had a pretty weird pain in my right quad. Especially noticeable when I had to run out wide for forehand shots. I didn't increase my weight in the squats and I didn't do any wide running beyond what I normally do.

The only thing that I know for sure has changed in the past few months is that I am literally faster. I have gotten to (and returned!) shots to my forehand that would have literally been impossible for me to get to before. So I know that my legs are getting stronger, but I just don't know why the pain started.

Now, about a week after the pain started, (and I haven't worked out my legs at all since then, but still have played some tennis,) the pain is still sort of there. It doesn't feel like soreness, because I can't really feel it unless I stretch my quads or go for those running shots.

Any ideas as to what this is, or why I'm feeling it now but not in the months before when I still did the exact same workouts and tennis?