Are Painful Leg Muscles And Dark Colored Urine Due To A Serious Concern?

I went to have cycling class two weeks ago and my legs muscle were extremely painful and my urine color turned dark blown. My doctor asked my to do the blood test and the result of my ALT came back 390 and my AST came back 1877. The ultrasound of abdominal report shows normal today. I have no history of liver problems. Thank you