Oh Frogga,

Of course you must get it checked out. If it's broken you don't want to leave it too long before getting it looked at; you'll have a much worse time later on if you don't (I realize you can hardly conceive of that, but it's true).

The sound of cracking from within the body is never good to hear, LOL...can't think of one instance of it being a positive sign.

I am certain you know all this already; just bite the bullet and go see,

I *really* hope it turns out to be just a bad bruise and something else made the cracking noise, though, good luck,
all the best