Getting Faster Pains

Sometimes, actually frequently, when I ride my bike really hard, I get these pains in my legs.

I don't know how to explain them. They feel like growing pains. I usually describe them as achy. It's this dull, constant pain in my quads, glutes, and basically the whole lateral sides of my legs.

Now my legs are really achy. I hope they are GETTING FASTER pains!