Liquid filled lumps on shins

I have these two weird lumps that show up on my leg. They tend to show up with exercise. They feel squishy and kind of like they're filled with liquid. They showed up about 15 years ago, when I was a teenager. I figure they're probably harmless, but curiosity is harder to kill than a cat.

I have these two weird lumps that show up on my leg. They tend to show up with exercise. They feel squishy and kind of like they're filled with liquid. They showed up about 15 years ago, when I was a teenager. I figure they're probably harmless, but curiosity is harder to kill than a cat.