if the drive in question is acting up, locking up, taking 3 minutes to open a file, etc., I'd do neither of the above (chkdisk/HDTune, etc), instead concentrating on backing up/recovering any of your needed files from it while you can. Then investigate to your heart's content after your data is safe. (If CrystalDiskInfo shows more than one or two pending/reallocated sectors and/or marginal health, your testing is pretty much over anyway...)
Although some drives can lose a sector, etc., and still last a long time, others might often degrade to being totally bricked /worthless within 5-20 operating hours....or less.