My cpk tested 1885, 24hrs after lifting weights. 7 days later, w/o exercise, tested 3800. on 5mg/day of crestor (rosuvastatin) for 2+ years. never high before. why?

Statin: Unclear whether this represents statin myopathy or weight lifting effects on the muscle. Safest course likely to stop the Crestor (rosuvastatin) and watch what happens to the cpk. If it clears, a rechallenge either with Crestor (rosuvastatin) or with less potent statin like Lovastatin with close CPK observation may clarify what's likely.

Check for myositis?: Doubtful that there would be sudden increase in CPK from consistent dose of statin. May result when dose changed, or other medications that affect metabolism of statin change. If this is not the case, then look for primary muscle problem: myositis comes to mind first. Also profound hypothyroidism and others.