Since you know your CK levels, I assume you've seen a doctor about this? Do you have other symptoms, like muscle tenderness, nausea, etc?
In any case, high CK and dark urine are among the signs of rhabdomyolysis (google it), which is not a Good Thing. It's a breakdown of skeletal muscle. It can be caused by too- vigorous exercise, especially when dehydrated, among other things. The broken-down proteins can clog the kidneys and cause kidney failure, with a resultant need for dialysis.
Some people have an hereditary condition that leaves them more prone to rhabdomyolysis.
One more thing: people taking statins to treat cholesterol problems may be more vulnerable to rhabdomyolysis.
I hope you are receiving medical care for this.