Stretching doesn't do jack squat for reducing muscle soreness.

Bret Contreras repeats what we've said here before:

Stretching and DOMS
DOMS (delayed-onset muscle soreness) typically arises within a day of exercise and peaks in intensity at around 48 hours. Many strength & conditioning practitioners believe that stretching before or after exercise will reduce soreness.

Henschke and Lin (2011) reviewed the research on this topic and concluded that stretching does not affect muscle soreness. Twelve total studies were included with a combined 2,377 participants. Pooled estimates showed that pre- and post-exercise stretching reduced soreness on average by one point on a 100-point scale one day following exercise, increase soreness on average by one point on a 100-point scale two days following exercise, and had no effect on soreness by day three.

Findings were consistent across settings (lab vs. field studies), types of stretching, intensity of stretching, populations (athletic, untrained, men, women) and study quality, so the conclusions are not likely to change with future research. To reiterate, stretching doesn't affect muscle soreness.