On a lot of runs, when I try to pick up the pace or go faster, my calves start to burn and hurt even though my breathing is usually not that bad... it feels like my legs cannot keep up with my breathing and I don't know what the problem is. I haven't been running super high mileage either (at least, the mileage I have been at is mileage I have been used to or run before, and I'm not doing a huge amount of workouts either). I took a day off but it still seems to be there, albeit not as badly and it feels like my legs start burning, hurting etc. but then I later check my pace and my pace isn't all that fast... I've been doing strides/hill sprints too. Is this just a funk? Will I get out of it soon? I have an important race in 2 weeks, but it's still important to maintain mileage...